I'm new too, but I think what you want to do may be accomplished by routing your sound signal to a VCA audio input, and routing the ADSR to the corresponding VCA voltage input. So, VCO->Korgasmatron->VCA input, and ADSR->VCA CV input. Try it anyway. That stereo mixer looks nice.

Looks like it should work fine after applying tweaks Moanerette suggested.