HD's/Wal-Mart/most Ace HW's won't cut steel keys for a reason -- it tears the heck out of their cutters. Dig out the Ye Old Phonebook, and find a real locksmith - ask if they'll cut steel keys.

Most dealer service depts should know a local source for a locksmith who has the right tools to cut the 'correct' key. Another weird source is BMW Motorcycle dealers (!!!!), as they also use steel keys, and can either cut M-B keys, or know someone who can.

I'll tell you my story-- needed a new key cut for my BMW K75s, and in a city of 1M++, there was no local locksmith who had the ability to cut my steel key. I had to drive to Austin to a dealer-recommended locksmith to have a key cut!!