How to call a Form System from a button in another form developed by UI API (SDK)

Hello everyone.

I have a form developed by UI API (SDK) in vb.Net, I need you to press a button, this opens a form of the system (eg Order) or User Defined Window (user-defined table) defined.

I have tried this in the click event of the button:

Private Sub Button6_ClickBefore (sboObject As System.Object, pVal As SAPbouiCOM.SBOItemEventArg, ByRef BubbleEvent As System.Boolean) Handles Button6.ClickBefore

            Dim f1 As SAPbouiCOM.Form

            Dim f2 As SAPbouiCOM.Form

            f1 = Application.SBO_Application.Forms.GetForm ("139", 0) 'System Form

            f1.Select ()

            f2 = Application.SBO_Application.Forms.GetForm ("11018", 0) 'User Defined window

            f2.Select ()

End Sub

In any case I issue the error "" Form - Not found [66000-9] "

What would be the correct way?

Greetings and Thank You