Since your sub features its own gain controls, why not just calibrate by ear? In other words, set the 950 so it's basically at 0 gain for the sub and raise only your sub gain knob from there. You may also want to play around with the phase knob to taste.
Other ideas; make sure you have your crossover selections set-up properly. Do you have small or large speakers? I think this is true on the 950, I own a 1050, but a "large" speaker selection won't send any information to the sub except if it's on the LFE channel of the DVD. Also, at what frequency do you have the crossover set? If you have the crossover set at like 40hz, on most recordings you won't get much sub. On movies, well, that's a different story.
Personally, just to test this out, I would set your speakers to "small", sub to "on", and put your crossover at 80 hz. If you're still not getting much from your sub, then you definitely have an issue.
Good luck and have fun!
Edit: One more thing, make sure you have your sub's crossover turned all the way up, as in, placed at the highest possible crossover point. This way it won't get in the way of the 950's settings.
[This message has been edited by Jason J (edited April 04, 2004).]