Reinyn,
Well, since you're looking for a 'tide me over' unit you may want to consider downgrading to the 970. It doesn't have quite the sonic capability of the 990, however if you're using the 3910 for SACD/DVD-A and presumably CD audio it may be acceptable.
The 970 has a 3-way toggle switch on the back to control how BM is applied to the 7.1 analog inputs (fixed 80Hz analog crossover/Bypass/Digital). With the toggle set to bypass you would get the behaviour you want for the 7.1 inputs and be free to set the digital processing settings independantly.