I am pretty sure it is done in the same fashion as in the 1998 BMW 528i , which  in that case you need to remove the cap on the inner door handle. then remove the phillip screw and disconnect door cable from handle. If you have rear roller sun blinds remove the plastic separator cover between the fixed glass and the window carefully and remove screw at the lower portion just above the door panel. Also remove the wood grain trim and remove the screws behind it. Carefully pry the outer edges of the panel away from the door panel. Once you have that done grab the solid door handle and pull up and away fairly forcefully. The black plastic retainer will be left on the door and it needs to go back on the panel to reinstall it. Carefully cut the black sticky butyl stuff that anchors the foam vapor barrier to the door. If you tear the vapor barrier replace it. Regulator should be accessible then.