For demo purposes, and to verify it can be done, I did it to this desktop (at {my surname}.homeip.net).  I have LD included with my Cingular and my roll-over minutes are piling up (55 hours and rising) so a call costs me nothing but my time.  If I'm not doing anything more important than slaying dragons on the computer it would be my pleasure to help walk you thru a setup.  (not to mention you cannot test outside access from the inside.)

But not today.  Today I have to install handrails over at my in-laws.  Gene no longer is able to ride, but his 600cc Honda dual-sport is still in his garage and he still shuffles over to look at it.