I haven't replaced an extractor on a P07/P09, but on the CZ 75 you don't have to drive the pin all the way out of the slide (makes starting it/driving it back in easier). Just drive it far enough out that you can pull the punch out and release the extractor, so you can replace the parts.
Also, been awhile, but I think on the CZ75 the pin is driven (from the top side of the slide) downward, to release the extractor. That way, when you drive it back in, you don't risk smacking the pretty part of the slide with your hammer/punch. I used a small piece of wood with a hole drilled into it so the pin wouldn't hit anything on it's way downward.