the TDAASTX.DLL is ancient, 32 bit and has not been touched in a long time. We connect direct to the servers, basically what that DLL does. I really don't remember what was in there or how to use it. I would recommend connecting directly as well. Or if you can wait, wait for our API, which will be basically one API that you can use to connect to whatever sources MT supports.
TWS API is a monster. That thing is Patches on top of patches. Its good for very specific programming (like yours) but nightmare to deal with for us, where we have to support all of their different security types, features. Symbols.