I just finished doing one of my rims, I did it all myself though. Popped the bead using a 2x6, and my truck. It took some fighting, some sweat, and a couple of beer. But I got the tire off.
Kal tire "gave me" 4 new stems, I just drilled the hole for the stem opposite the original hole. Put the inner stem in upside down, and Voila!!
One flipped wheel, and it didn't cost me a thing.. (The tire was a lot easier to get back on, than it was to get off)
I did worry that the inner stem would blow out while I was seating the bead, but it worked great.
Now I just have to do the other one.. lol