diff --git a/src/cmd/cgogen.go b/src/cmd/cgogen.go
old mode 100644
new mode 100755
index c67a90d..c91d4a9
--- a/src/cmd/cgogen.go
+++ b/src/cmd/cgogen.go
@@ -609,7 +609,7 @@ func processFunc(fast *ast.File, fdecl *ast.FuncDecl, outFile *jen.File, dependa
 			}
 			if len(typeName) > 0 && rune(typeName[0]) == '[' {
 				typeName = "*C.GoSlice_"
-			} else if dealOutStringAsGostring && typeName == "string" {
+			} else if typeName == "string" {
 				typeName = "*C.GoString_"
 			} else if IsBasicGoType(typeName) {
 				typeName = "*" + typeName
@@ -828,8 +828,12 @@ func getCodeToConvertInParameter(_typeExpr *ast.Expr, packName string, name stri
 				if !isPointer {
 					leftPart = leftPart.Op("*")
 				}
-				leftPart = leftPart.Parens(jen.Op("*").Id(packName).Id(".").Id(typeName)).
-					Parens(jen.Qual("unsafe", "Pointer").Parens(jen.Id(argName(name))))
+				if typeName == "FeeCalculator" {
+					leftPart = jen.Id(name).Op(":=").Add(getCallbackCode(name))
+				} else {
+					leftPart = leftPart.Parens(jen.Op("*").Id(packName).Id(".").Id(typeName)).
+						Parens(jen.Qual("unsafe", "Pointer").Parens(jen.Id(argName(name))))
+				}
 				return jenCodeToArray(leftPart)
 			}
 		}
@@ -954,6 +958,7 @@ func isInplaceConvertType(typeName string) bool {
 }
 
 /* Process a type expression. Returns the code in C for the type and ok if successful */
+// typedata
 func processTypeExpression(fast *ast.File, type_expr ast.Expr,
 	packageName string, name string,
 	definedTypes *[]string,
@@ -1368,6 +1373,23 @@ var basicTypesMap = map[string]string{
 
 var packageSeparator = "__"
 
+func getCallbackCode(varName string) *jen.Statement {
+
+	varFunction := jen.Func().Params(
+		jen.Id("pTx").Id("*coin.Transaction"),
+	).Parens(jen.Uint64().Op(",").Error()).Block(
+		jen.Var().Id("fee").Id("C.GoUint64_"),
+		jen.Id("handle").Op(":=").Id("registerTransactionHandle").Call(jen.Id("pTx")),
+		jen.Id("result").Op(":=").Id("C.callFeeCalculator").Call(jen.Id("_"+varName), jen.Id("handle"), jen.Id("&fee")),
+		jen.Id("closeHandle").Call(jen.Id("Handle").Call(jen.Id("handle"))),
+		jen.If(jen.Id("result").Op("==").Id("SKY_OK")).Block(
+			jen.Return(jen.Id("uint64").Call(jen.Id("fee")), jen.Nil())),
+		jen.Return(jen.Lit(0), jen.Qual("errors", "New").Call(jen.Lit("Error calculating fee"))),
+	)
+
+	return varFunction
+}
+
 func getPathPackage(path string) (packagePath_ string, mainPackagePath_ string) {
 
 	index := strings.LastIndex(path, "/")
diff --git a/vendor/vendor.json b/vendor/vendor.json
deleted file mode 100644
index aef8800..0000000
--- a/vendor/vendor.json
+++ /dev/null
@@ -1,13 +0,0 @@
-{
-	"comment": "",
-	"ignore": "test",
-	"package": [
-		{
-			"checksumSHA1": "GtqEEHjKsMGUSCqjPyKLi+DfcEs=",
-			"path": "github.com/dave/jennifer/jen",
-			"revision": "724ff9887965e893831e9493011297e6bc01ecb4",
-			"revisionTime": "2019-11-26T19:34:09Z"
-		}
-	],
-	"rootPath": "github.com/fibercrypto/cgogen"
-}