Diagnostic Adapters: Compatible with Non-VAG Vehicles?

Hi,
After I built the diagnostic adapter myself and it actually works, my question is: can I use other software besides VAG-Com?
I especially like:
Freescan.
allg. OBD-2 Software.
Unfortunately, I haven't had any success with anything other than VAG-COM... is that really not possible?

Sure, here's the translation:

'Thank you very much.'
Sebastian.