First I tried modulating the pitch of the polysynth, but the maximum update rate is very slow not even into audio frequency... Filter FM was a bit more succesfull, but the modulation rate seem to still be below the host audio rate. But I did actually get some very interesting clunky digital sounds reminiscent of a Commodore 64 this way.
So, I went to the new modulator system:
I managed to patch up a FM mono synth by using a dc offset and keytracked LFOs. Setting the keytracking was a pain in the ass and required an oscillosope... The LFO freq can be set in khz, but the keytrack values are not logical. None of the even values result in correct octave tracking. So I set the thing up by drawing a custom tracking curve. Amazingly enough, cross modulation of the LFOs is possible, altough it produces a somewhat noisy result. What kind of tricks have people found out when building their own synths inside BW? (update: I heard that in 2.2 a pitch option is available for the LFO sync. Still, this way produced a nice, just a little bitt off sound like on some abused analog gear)
Finally I managed to create a pretty nice distorted three-voice parallel filtered lead that can cut through steel.