@d-healey sigh Alright, i figured it out. I didn't tick the "IsPluginParameter" box on the buttons and knobs. It works fine now. facepalm
again, thanks for your patience, i appreciate it. you earned yourself a place in the "credits" screen of the plugin, which i need to figure out how to code so it shows up when a small button is pressed.
The buttons do show up now as MIDI-controllable, but still no sound is happening (almost like a full bypass), but that i'll figure out in a bit...