diff --git a/pkg/rpc/request/txBuilder.go b/pkg/rpc/request/txBuilder.go
index 563abba7b..84215314d 100644
--- a/pkg/rpc/request/txBuilder.go
+++ b/pkg/rpc/request/txBuilder.go
@@ -29,7 +29,7 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 			}
 			emit.Bytes(script, str)
 		case smartcontract.SignatureType:
-			str, err := fp.Value.GetBytesHex()
+			str, err := fp.Value.GetBytesBase64()
 			if err != nil {
 				return err
 			}
@@ -83,12 +83,10 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 			if err != nil {
 				return err
 			}
-			err = ExpandArrayIntoScript(script, val)
+			err = ExpandArrayIntoScriptAndPack(script, val)
 			if err != nil {
 				return err
 			}
-			emit.Int(script, int64(len(val)))
-			emit.Opcodes(script, opcode.PACK)
 		case smartcontract.AnyType:
 			if fp.Value.IsNull() {
 				emit.Opcodes(script, opcode.PUSHNULL)
@@ -100,6 +98,22 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 	return script.Err
 }
 
+// ExpandArrayIntoScriptAndPack expands provided array into script and packs the
+// resulting items in the array.
+func ExpandArrayIntoScriptAndPack(script *io.BinWriter, slice []Param) error {
+	if len(slice) == 0 {
+		emit.Opcodes(script, opcode.NEWARRAY0)
+		return script.Err
+	}
+	err := ExpandArrayIntoScript(script, slice)
+	if err != nil {
+		return err
+	}
+	emit.Int(script, int64(len(slice)))
+	emit.Opcodes(script, opcode.PACK)
+	return script.Err
+}
+
 // CreateFunctionInvocationScript creates a script to invoke the given contract with
 // the given parameters.
 func CreateFunctionInvocationScript(contract util.Uint160, method string, param *Param) ([]byte, error) {
@@ -107,12 +121,10 @@ func CreateFunctionInvocationScript(contract util.Uint160, method string, param
 	if param == nil {
 		emit.Opcodes(script.BinWriter, opcode.NEWARRAY0)
 	} else if slice, err := param.GetArray(); err == nil {
-		err = ExpandArrayIntoScript(script.BinWriter, slice)
+		err = ExpandArrayIntoScriptAndPack(script.BinWriter, slice)
 		if err != nil {
 			return nil, err
 		}
-		emit.Int(script.BinWriter, int64(len(slice)))
-		emit.Opcodes(script.BinWriter, opcode.PACK)
 	} else {
 		return nil, fmt.Errorf("failed to convert %s to script parameter", param)
 	}
diff --git a/pkg/rpc/request/tx_builder_test.go b/pkg/rpc/request/tx_builder_test.go
index 62ae926d1..1a5fd4f1a 100644
--- a/pkg/rpc/request/tx_builder_test.go
+++ b/pkg/rpc/request/tx_builder_test.go
@@ -1,7 +1,7 @@
 package request
 
 import (
-	"encoding/hex"
+	"encoding/base64"
 	"fmt"
 	"math/big"
 	"testing"
@@ -23,49 +23,52 @@ func TestInvocationScriptCreationGood(t *testing.T) {
 		script string
 	}{{
 		ps:     Params{{RawMessage: []byte(`"transfer"`)}},
-		script: "c21f0c087472616e736665720c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "wh8MCHRyYW5zZmVyDBRvRZFizuskiwcewVfZ5Pb9Jv2+UEFifVtS",
 	}, {
 		ps:     Params{{RawMessage: []byte(`42`)}},
-		script: "c21f0c0234320c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "wh8MAjQyDBRvRZFizuskiwcewVfZ5Pb9Jv2+UEFifVtS",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[]`)}},
-		script: "10c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "wh8MAWEMFG9FkWLO6ySLBx7BV9nk9v0m/b5QQWJ9W1I=",
 	}, {
-		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "ByteString", "value": "AwEtR+diEK7HO+Oas9GG4KQP6Nhr+j1Pq/2le6E7iPlq"}]`)}},
-		script: "0c2103012d47e76210aec73be39ab3d186e0a40fe8d86bfa3d4fabfda57ba13b88f96a11c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "ByteArray", "value": "AwEtR+diEK7HO+Oas9GG4KQP6Nhr+j1Pq/2le6E7iPlq"}]`)}},
+		script: "DCEDAS1H52IQrsc745qz0YbgpA/o2Gv6PU+r/aV7oTuI+WoRwB8MAWEMFG9FkWLO6ySLBx7BV9nk9v0m/b5QQWJ9W1I=",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Signature", "value": "4edf5005771de04619235d5a4c7a9a11bb78e008541f1da7725f654c33380a3c87e2959a025da706d7255cb3a3fa07ebe9c6559d0d9e6213c68049168eb1056f"}]`)}},
-		script: "0c404edf5005771de04619235d5a4c7a9a11bb78e008541f1da7725f654c33380a3c87e2959a025da706d7255cb3a3fa07ebe9c6559d0d9e6213c68049168eb1056f11c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "DGDh51/nTTnvvV17TjrX3bfl3lrhztr1rXVtvvx7TTznjV/V1rvvbl/rnhzfffzRrdzzt7b3n1rTbl1rvTp3vbnlxvdrd9rTt5t71zrnn13R317rbXdzrzTj3Xrx5vXTnp8RwB8MAWEMFG9FkWLO6ySLBx7BV9nk9v0m/b5QQWJ9W1I=",
+	}, {
+		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Signature", "value": "Tt9QBXcd4EYZI11aTHqaEbt44AhUHx2ncl9lTDM4CjyH4pWaAl2nBtclXLOj+gfr6cZVnQ2eYhPGgEkWjrEFbw=="}]`)}},
+		script: "DEBO31AFdx3gRhkjXVpMepoRu3jgCFQfHadyX2VMMzgKPIfilZoCXacG1yVcs6P6B+vpxlWdDZ5iE8aASRaOsQVvEcAfDAFhDBRvRZFizuskiwcewVfZ5Pb9Jv2+UEFifVtS",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "String", "value": "50befd26fdf6e4d957c11e078b24ebce6291456f"}]`)}},
-		script: "0c283530626566643236666466366534643935376331316530373862323465626365363239313435366611c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "DCg1MGJlZmQyNmZkZjZlNGQ5NTdjMTFlMDc4YjI0ZWJjZTYyOTE0NTZmEcAfDAFhDBRvRZFizuskiwcewVfZ5Pb9Jv2+UEFifVtS",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Hash160", "value": "50befd26fdf6e4d957c11e078b24ebce6291456f"}]`)}},
-		script: "0c146f459162ceeb248b071ec157d9e4f6fd26fdbe5011c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "DBRvRZFizuskiwcewVfZ5Pb9Jv2+UBHAHwwBYQwUb0WRYs7rJIsHHsFX2eT2/Sb9vlBBYn1bUg==",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Hash256", "value": "602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7"}]`)}},
-		script: "0c20e72d286979ee6cb1b7e65dfddfb2e384100b8d148e7758de42e4168b71792c6011c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "DCDnLShpee5ssbfmXf3fsuOEEAuNFI53WN5C5BaLcXksYBHAHwwBYQwUb0WRYs7rJIsHHsFX2eT2/Sb9vlBBYn1bUg==",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "PublicKey", "value": "03c089d7122b840a4935234e82e26ae5efd0c2acb627239dc9f207311337b6f2c1"}]`)}},
-		script: "0c2103c089d7122b840a4935234e82e26ae5efd0c2acb627239dc9f207311337b6f2c111c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "DCEDwInXEiuECkk1I06C4mrl79DCrLYnI53J8gcxEze28sERwB8MAWEMFG9FkWLO6ySLBx7BV9nk9v0m/b5QQWJ9W1I=",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Integer", "value": 42}]`)}},
-		script: "002a11c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "ACoRwB8MAWEMFG9FkWLO6ySLBx7BV9nk9v0m/b5QQWJ9W1I=",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Integer", "value": "42"}]`)}}, // C# code doesn't use strict type assertions for JSON-ised params
-		script: "002a11c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "ACoRwB8MAWEMFG9FkWLO6ySLBx7BV9nk9v0m/b5QQWJ9W1I=",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Integer", "value": true}]`)}}, // C# code doesn't use strict type assertions for JSON-ised params
-		script: "1111c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "ERHAHwwBYQwUb0WRYs7rJIsHHsFX2eT2/Sb9vlBBYn1bUg==",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Boolean", "value": true}]`)}},
-		script: "1111c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "ERHAHwwBYQwUb0WRYs7rJIsHHsFX2eT2/Sb9vlBBYn1bUg==",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Boolean", "value": false}]`)}},
-		script: "1011c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "EBHAHwwBYQwUb0WRYs7rJIsHHsFX2eT2/Sb9vlBBYn1bUg==",
 	}, {
 		ps:     Params{{RawMessage: []byte(`"a"`)}, {RawMessage: []byte(`[{"type": "Boolean", "value": "blah"}]`)}}, // C# code doesn't use strict type assertions for JSON-ised params
-		script: "1111c01f0c01610c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "ERHAHwwBYQwUb0WRYs7rJIsHHsFX2eT2/Sb9vlBBYn1bUg==",
 	}}
 	for i, ps := range paramScripts {
 		method, err := ps.ps[0].GetString()
@@ -76,7 +79,7 @@ func TestInvocationScriptCreationGood(t *testing.T) {
 		}
 		script, err := CreateFunctionInvocationScript(contract, method, p)
 		assert.Nil(t, err)
-		assert.Equal(t, ps.script, hex.EncodeToString(script), fmt.Sprintf("testcase #%d", i))
+		assert.Equal(t, ps.script, base64.StdEncoding.EncodeToString(script), fmt.Sprintf("testcase #%d", i))
 	}
 }