Arghh... stripped oil pan drain bolt on 3B!

[Peter Schulz <schulz@iatcmail.ed.ray.com>]

Well, it seems that the "Monkey Lads" have struck again.

I'm in the process of dropping the oil pan and oil pump on my
recently purchased 1991 200 TQW.  I decide that it's a good idea
to drain the oil first.  I take a look at the drain bolt and
argh!!!! the edges are rounded as if the bolt was made of butter.
And to make matters worse, there is NO copper gasket between the 
bolt and the aluminum (aluminium) oil pan.

%#^&@%#^%@^!!!

I try a 17mm 6 point with a breaker bar to no avail.  I then 
hammered a Sears Craftsman 16mm six pt onto the bolt, and spray
Liquid Wrench onto the (barely) viewable thread. And then 
try out my new birthday present...an air compressor with air
tools!.

I try the 1/2 inch air wrench (suppposedly 200-230 ft lb.s torque)
in the reverse position to loosen the bolt.

Nothing. No movement at all. %#^%&^@&#^&@!!!

Now before I lose what little is left of the flats on the formerly
17mm bolt, I need your advice.  Should I try heat (I'm nervous
because of the aluminum oil pan), an easy out (do-able, but will it
take the torque?), or should I try the messy job of dropping the
oil pan with the oil in it, and then sending the pan/bolt to a 
machine shop?

Any advice appreciated.

-Peter Schulz
1991 200 TQW
1990 CQ
schulz@res.ray.com

-ps> the timing belt and H2O pump are off the car, so DRIVING it 
to a repair shop is not an option.