Have this by my desk (don't ask!)... assuming it's the same thing (if someone can confirm)... it may give you an idea of what you're aiming for:
I've not tried going through the access panel, but even with the lights out I can't believe what a fiddly job it is! I can barely get the damn cover off, maybe it's easier when the light's bolted to something.
EDIT: In defense of my remove the bumper strategy... if I am having trouble trying to access or do something (to the point of say removing a wheel) I prefer to get at it (bumper off) and look at it properly and access the problem. Otherwise I tend to get frustrated and break things. But yes, I appreciate the long way is possibly not the best advice for others. Also should have realised more experienced advice would be along shortly