How does Receptor communicate patch to VST?

[hopkihc]

I'm wondering what functionality a VST needs to support in order to respond to a program change from Receptor software (as opposed to program change within the VST GUI).

Can anyone comment on how this works?

I know I've had issues with certain (unsupported) VSTs that essentially work (install/register/working GUI) except for responding to a patch change request from the Receptor. I can save a source program or a single or whatever, but recalling it does not actually change the sound in the VST.

-John