If you speak about Aftertouch (AT) this is a controller source. Within the controller routing inside MONTAGE's Motion Control Synthesis Engine we have to think of sources and destinations. So you can't route one source to another. Of course you can route the destination, which is assigned to AT "re-route" to the MW. This could be even an additional routing or a replacement for the existing one. This is all done in Part edit mode > Mod / Control > Control Assign.