You have the perfect excuse now to pull the engine so removing the pan will be a breeze, and you will have the opportunity to do the rear seal. And while your at it, degrease the engine, do a new thermostat, water pump, stuff that is hard to get to installed.

I had the pan off my 603, but it was out of the car. Cant answer your main question, but you could try getting the pan off by lifting the engine and let us know if you were successful.