There's a large windage piece that fits into a dovetail on the slide, with a set screw. The elevation part (the part I've replicated) is captive in the windage piece, with a spring underneath pushing up, and the adjustment screw on top of a nub that protrudes from the front of it.
edit: bah...I just re-read your post and see that you said front sight not rear. I don't think the front can be replaced without doing something custom. The fiber optic is nice too.
I'm sure I could file down the adjustment screw or something, but the gun is really beautiful man...I don't wanna do that.