I don’t have a GAIA myself, but I found this in the SOS review:
There is one slight down side for computer interaction, though, and it relates to Roland’s eternal struggle with the concept of MIDI continuous controllers. I really hoped to use all those lovely knobs and sliders to control my soft synths. Initially, all looked good; I turned a few knobs and MIDI CCs spilled forth. It was only when I began assigning parameters to some objects in Logic that I realised the envelope sliders weren’t playing ball — they weren’t sending any data. A browse of the manual revealed an extra edit mode that forces these sliders to generate System Exclusive data — but I could find no way to address the CC oversight. Let’s hope this can be remedied in an OS revision not too far in the future.
No idea if this has been fixed, but it seems that you can use most knobs and sliders to control VST’s anyway. It would require some keybinding though, turning the LFO knob will not automatically find you the LFO knob on your VST, you’d have to connect the 2 manually. (which should be easy enough using quickcontrols or midi learn.)