The opener had originally two cheap plastic lamp holders on the side. The problem was that it was not designed for CFLs. The thick body of CFLs did not allow to be screwed in deep enough to have an electrical contact inside the lamp holders. I solved this by adding a bit of solder to the CFL's electrical contact. Not ideal though.
I replaced one of the two original plastic lamp holders and added a third one to the front. The other original one on the side would take more work to replace because there is a circuit board behind it from inside.
Yes, I passed the wiring through the housing.
Now I can use it with any kind of bulb, multiple bulbs, no matter the shape or size.