You don't have to break anything, Rafa. Just unscrew the retaining ring and get rid off the glass. Minimum focus varies. It can be as close as 4cm (look at one of my posts on this very topic) and a sample shot is in your "fun with the 17mm" thread.
Here is a Oly-D 17/2.8 shot (Barcelona/Summer):
Here is one with the 17/2.8+ GW-1 (Barcelona/Summer):