How do I define the variable identification as the curve name in the picture switch function to the extended trend picture?

VBA Code:
Sub change_curve_varname_varid()
'this procedure changes the name of the curve from the variable name to variable identification
Dim myFunc As RtFunction
Dim myVar As Variable
Dim i
Dim numCurves As Integer
Set myFunc = MyWorkspace.ActiveDocument.RtFunctions.Item("a")
If Not myFunc Is Nothing Then

numCurves = myFunc.DynProperties("PictFilter[0].Curve[-1]")
For i = 0 To numCurves - 1
Set myVar = myFunc.DynProperties("PictFilter[0].Curve.VarInfo.Variable")
If Not myVar Is Nothing Then
myFunc.DynProperties("PictFilter[0].Curve.GraphName") = myVar.Tagname
End If
Next i
End If
End Sub