How can I get value of User Defined Field in SAP B1?

Hi all,

How can I get UDF value from system form of SAP B1?

Actually I know how I can get value from field like this

        Dim oForm As SAPbouiCOM.Form
        Dim oEditTotal As SAPbouiCOM.EditText
        oForm = SBO_Application.Forms.GetForm("133", 1)
        oEditTotal = SBO_Application.Forms.ActiveForm.Items.Item("2").Specific

But if I try to use UDF like this it bring error message

        Dim oForm As SAPbouiCOM.Form
        Dim oEditTotal As SAPbouiCOM.EditText
        oForm = SBO_Application.Forms.GetForm("133", 1)
        oEditTotal = SBO_Application.Forms.ActiveForm.Items.Item("U_return").Specific

How can I do that?

Please anyone can help me