Tricky. I've been reading up on automation, preparing to create an automation server, and the COM object you are talking to will need to be able to understand the object you are passing.

If you are passing something that looks like a string, it may well get interpreted as such in which case you will have the same problem.

I think what you need to do is to pass an object that the COM automation can handle in a binary fashion - a BLOB or similar.