I think you'd be better off writing a program or plugin for the TV Server that acts as a go-between.
Maybe take a look at the
TV Client program, perhaps you could add a simple communications method between it and XBMC.
If I knew anything about coding for XBMC or indeed anything about Python I would try to help you out. But I'm afraid I don't.
However, if there is anything I can do MediaPortal plugin or windows app wise then please let me know. I have two XBMC Xbox's in my house and would love to use them for live digital TV viewing.
Just simple tv viewing would be an awesome first step. Also, there is
another ongoing project with the same lofty aims. It's been progressing extremely slowly, so perhaps you can give it the injection of developer time that it needs.
Best of luck and please do keep us informed of your progress...
Cheers,