If you set the speakers to large, and bass to LFE+Main, then both your mains and subwoofer pre outs will get full range signal.
That is the case regardless of stereo or direct mode. I am 100% sure that is the case for the X4000H series. You can have the sub on even in pure direct mode but no Audessy that's all.
For the 3000 series, I am 90% sure, but
@Verdinut can confirm that since he has the x3700h.