I believe you are limited to what is assignable to the controller IAs.
On the MFC, ....hit Edit, Midi and page 7x ......this will get you to the IA page. Hit the up/down buttons to get you to the IA you want to assign then hit the page button 1x and again choose the effect/parameter you want. You'll find Amp X/Y, Cab X/Y as well as other effects in that option.
As far as I know you can't have an IA function as a "Wild Card" or "Jack pot" and assign separate effects to the same IA for different presets.
It would be nice to have this option though.