Opening Office 2007 Documents from in memory storage - How?

I'm a C++ developer wrestling with updating an application that had made extensive use of the IStorage interface to open pre-Office 2007 documents from in-memory storage (via ILockBytes).

If you are still following me so far, you probably know that the new Office Document formats are incompatible with IStorage containers. The application I'm trying to update, relied 开发者_Python百科upon the IPersistStorage interface that all Office applications have, and the code as written calls the load method of IPersistStorage to read in a document from IStorage interface.

So the question is:

What kind of COM interfaces are available to me to read in, from an in memory container, an Office 2007 document?

I've been struggling with pretty much the same problem, to read and write from database storage.

Right now, I'm thinking that the best way might have to be to use the WebDAV-support, and use a web server to implement WebDAV to read from and write to the database.

It's a mess, though... other pointers would be welcome :-)