We've been developing software recently that uses the new Windows deployment
library (wimgapi.dll / imagex.exe).

The software makes Windows Vista images in WIM file format similar to the
Microsoft ImageX tool. Windows Vista ships with a standard 2.5GB WIM file on
the install media called INSTALL.WIM. Our WIM images naturally contain
pretty much the same stuff that is in this file. We've been looking for ways
to package only the 'difference' between our image and the standard
INSTALL.WIM. For reasons I won't bother to explain this would greatly help
our software if we only needed to store the small 'difference' rather than
multiple 2-3GB files.

We've developed a method of achieving the above which is both small and very
fast. However, during the final testing of this we found the function
WIMSetReferenceFile partially documented in the WIMGAPI documentation. This
looks like it may be able to do the thing we're trying to achieve. However,
the Microsoft documentation is very sparse and doesn't really indicate what
it is intended to be used for. We've actually put together some
proof-of-concept code to try out WIMSetReferenceFile - it works (ie doesn't
return an error!) but doesn't actually seem to do anything either during a
WIM Capture or Apply operation.

Does anyone know what WIMSetReferenceFile is for?

James