In my experience of using Multi-Track Audio applications, you can only normally select one driver, ASIO or Multimedia/DirectSound, etc.
Yes, I've seen that certain application, like Traktor Dj, don't allow selecting more than one output driver: this certainly simplifies a lot.
The driver for your Aureon may be locking-out all other driver options once one has been chosen and loaded. Your drivers may not support multi-client access, but 3rd party drivers (ala ASIO4ALL) may allow you to override this feature.
This is an interesting point: do you mean that faulty drivers could be replaced for example by ASIO4ALL? Or only sound cards which don't support ASIO natively can make use of ASIO4ALL?