http://bugs.winehq.org/show_bug.cgi?id=23115
--- Comment #6 from Vincent Povirk madewokherd@gmail.com 2010-06-14 09:17:52 --- There don't seem to be many ways to access the standard file-based implementation. So far I've only found StgGetIFillLockBytesOnFile, which is still a stub in the spec.
For your test, you could use any implementation of ILockBytes whose Stat method behaves the way you want.
The patch no longer applies to current Wine. The Stat implementation is now shared between the different types of storage objects. I guess we need an internal method for getting the filename (if applicable) that depends on the particular storage implementation.