@axiomcrux, this FAQ might be useful: http://www.eigenlabs.com/faq/eigend/how-do-i-route-the-eigenharps-controllers-eg-stri/
When you use activate parameter 3 (pressure) for a certain Audio Unit parameter, you should get it to work. Note though that this works at the level of audio unit parameters, it doesn't automatically generate MIDI CC messages. So you either need to do that conversation yourself (which I do in Bidule and I'll post a how-to about that soon), or you'll have to activate the knob or value of your audio unit as a 'host automation' parameter, which is usually exported as an audio unit parameter and thus is available through this grid mapping.