[s-cars] Can't open driver's back door

[weski at verizon.net]

Greetings S-Heads

Patient is my 95 S6 sedan and a couple weeks ago I needed to put some 
things in the back seat and could not get the door open.  It was -16f so 
I figured it might literally be frozen so I just tossed my stuff in the 
front door and onto the passenger seat. Fast forward to this past 
weekend and after the car sat in my garage for 7 days I had a dead 
battery.  I went to open the driver's side back door to put my trickle 
charge on the battery and was reminded that the door won't open.

Long story short, I got the battery charged by leaning over the front 
seats to open the rear seat bottom and put the charger on. Now I need to 
figure out how to get the door open so I can get to repairing it.

I tried both the exterior and interior handles and both move but don't 
have any affect or noticeable sound.  When I lock and unlock the car 
with the central locking system I can't see the lock knob for the back 
door move at all.  The other 3 doors and trunk work as expected with the 
central locking system.

Does anyone have any ideas or tricks to open a back door in this 
situation?  I'm thinking there isn't any way to remove the interior 
panel while the door is closed - is there?  Is my best option to unbolt 
the front edge of the door from the hinges?

TIA,

Paul
95 S6 w/261k miles and a stubborn door