Ok, I found out that I was using the wrong *.dll or *.tlb
when I am using the *.tlb from here:
C:\ProgramData\mgcSDD\win64\TLB\MGCPCB.tlb
then I have the Enumeration mentioned above, and a few more functionalities,
like Setting the Colors/Pattern on the Layers, and creating color objects via
Dim colO As MGCPCB.ColorPattern colO = pcbApp.Utility.NewColorPattern(0, 255, 255, 0, False, False)
Bye