I had no problem. I purchased the proper 12pt. Bit from an auto parts store. They are called a "Triple Square" bit used on European cars such as VW and Audi and was around $8.00.
Sears, Snap-On also have them as far as I know.
I soaked each bolt in a penetrating oil overnight and was careful when removing them, tightening them slightly first to break the bond if they did not break free immediately.
I was very careful to mark the position each of the center spokes on each rim and also mark which rim was with which centre, so there would be no problem reassembling them exactly the way they came apart.
If you have the hidden valves it helps as there is only one position they can go back together as the valve/bolt is different than all the rest.
When reassembling them I tightened them all lightly by hand at first to snug the centre back in the rim and then tourqued each of the bolts evenly being careful to tighten opposites in a cross pattern to make sure the centre seated properly in the rim.
It really was no big deal. I have driven the car a lot since and there were no balance issues at all.
Good luck with the project. Send me some pix when they are done.

 

I have outlined the process in my last post. Hope it helps you.

 

Thanks a lot Growler! I've never heard of that type of socket. I will let you know how it goes. You have given me the best solution to changing my wheels. I like the wheels, I just prefer them blacked out. These forums and people like you are so helpful!