Programming SaveAs w/an assembly

I am creating an API driven document creation system, and Ineed to be able to save an assembly uncer a new name in API.

Here is what I tried:
Set swModel2 = swApp.OpenDoc6(strBaseAssy, swDocASSEMBLY, _
swOpenDocOptions_Silent, "", nErrors, nWarnings)

Set swModelDocExt = swModel2.Extention
bolRetVal = swModelDocExt.SaveAs(strAssyToReference, 0,swSaveAsOptions_Silent, Nothing, nErrors, nWarnings)

It works OK for parts but not assemblies. What do I use in order tosave an assembly unde a new name?
Thank You,
-plhSolidworksApi macros