Neither. I run them just like I always have, externally, with the same hooks GetObject for running applications, CreateObject for ones that I am starting. Like this:
com_version = 9
mskeng = CreateObject("MGCPCBEngines.MaskEngine." & com_version)
Even when I have explicitly stated the com version like this, the engines and Parts editor have failed to launch. I had previously verified that the com version was 9, using uncompiled code to do the same thing.
Thanks for your help, Jeremy. It's much appreciated.