Our general policy has been to not support Firefox betas. Is there a reason you're using a beta? Also, do these sites autopopulate with older versions of Firefox?
Well, the first RC is just around the corner, so it would be nice if PWM was working and well tested by the time 3.5 is released, which isn't far away now...

It will be ready for 3.5. I'd like to start testing / debugging when an RC is released--RC means no more changes unless absolutely critical. If I spend my time testing / debugging against a beta, there is a chance that the next beta (or RC) won't work with whatever I did for the previous beta.