Door panel comes off as follows:
Using a plastic blade of some sort (or wrap a butter-knife with tape), pry off the tweeter casing and unplug the speaker. Next, undo the four screws mentioned above, using a Ph2 driver. Start prying the panel loose, using hands / blade. Beware that the mid-tone speaker is attached to the panel on a fairly short wire, so make sure you don't yank it off. It unplugs from the terminals on the speaker.
With the panel off, you'll find that everything is covered up by a foam liner. Dont try to pull this off - it's better to just cut it cleanly where you have to and stick it back together with duct tape.
Assembly is reverse procedure, but make sure the door handle screws hit where they're supposed to.
Good luck!
Henrik