The Danlock

The object of this puzzle is, of course, to open the lock and to release the locked key. Two keys are provided. Unfortunately, one key is locked and the other is broken... Can you find the key to the solution?
No external tools are allowed, just the lock and the two keys provided with it. Not even the small metal ring that holds the two broken parts of the key, neither the bag that comes with the DanLock.
This puzzle is available directly from Dan Feldman (feldman@bezeqint.net). Grand Illusions may also carry this piece.