Audi 80 Offside Rvm

[Spinal]

Hello! This is my first post, but Im already asking for help. My mother managed to reverse into a pole, and destroyed her external RVM (offside). I have bought a new one and want to replace it for her. I have managed to remove the old one (twisting it sideways and unscrewing the two 6-point-star screws; then disconnecting the cable). My prolem is this, I cannot seem to be able to reconnect the cable to the new one as the wire is WAY too short to reach it othe than when its mounted. So my conclusion is that I should remove a panel from the inside... am I right? Or am I doing something totally stupid and wrong?

Thanks,
Michele