I am having this exact same problem. I needed to replace the light bulb--which I found out is not just a replaceable minibulb
(like on my e28s), but a whole minibulb assembly. I already had the minibulb ready to go and just swapped in a minibulb socket I had leftover from my e28 days--and it works great. Anyhow, I pulled the HVAC panel out okay, but it did take some jostling to get the stubborn two bottom tabs out.
It looks like if I take out the center console piece that sits directly below the panel it will give me enough space to get the tabs to insert at the right angle--but I don't see a ready way to pull that part of the center console out. I pulled apart the shift boot (5-speed) and didn't see any screws that would loosen the console, but I didn't pull things apart searching (yet), as I had to drive the car right away.
It would be great to hear from anyone who has put this back in there WITHOUT breaking the tabs off.