Has anyone succeeded in getting Outlook 2007 form regions to work with
a C++ add-in? The publicly available sample code is in C# and I have
no problem getting that to work. But, I'm running into a wall getting
regions to work in C++.

If I'm not mistaken, form regions work by having the add-in object
supply both the IDTExtensibility2 and the _FormRegionStartup
interfaces. To satisfy this, I have my add-in class inherit from two
instances of IDispatchImpl, one for each of the interfaces. However,
when this add-in is installed in Outlook 2007, the _FormRegionStartup
interface never gets used. In the debugger, I can see that the add-in
is connected (OnConnection) and that Outlook 2007 calls QueryInterface
to obtain the _FormRegionStartup interface. However, Outlook doesn't
do anything with the _FormRegionStartup interface once it is available.
The functions in the interface are never called.

So, if you've succeeded in getting this feature to work in a c++
add-in, did you have any trouble getting there? Would you be willing
to post sample code?