yo, have you sold your 4000 yet bcuz what you asked to do can be done.

assuming that you want the 4000 to be the master controller. first you would have to switch to slave mode on the ASRX in the midi section (sometimes referred to as midi external/internal) hook up a midi cable from midi in (ASRX) to midi out-A (4000).

make sure you have the slave synth (ASRX) in multimode so that you can play more than one sound simultaneously. they would both sync to midi clock and make sure that the midi kybd controller's local is set to off. this setup should make this request run real smooth. hope this helps.
makin heat all the way to Zion! choose ye this day whom you will serve.........c'mon saints you know the rest. yeahhhh.