Comment 139 for bug 357456

(In reply to Zebediah Figura from comment #132)
> Windows appears to have its own set of internal interfaces, e.g.
> {000c101c-0000-0000-c000-000000000046} "Msi install server". We actually
> have an IDL for these in msi.dll, since evidently some program tries to
> create one. But these interfaces are all internal; we don't even know the
> vtbls. It would appear that this approach would be close enough to
> replicating that one.

Does this help?
https://www.winehq.org/pipermail/wine-cvs/2007-January/029786.html
https://msdn.microsoft.com/en-us/library/windows/desktop/aa369432(v=vs.85).aspx