AD/OD integration clarification

A couple things in the white paper I could use clarified please. f First when assigning an AD users home directory in AD it said I would get a notification that the host folder already exists when the notification I got was that the folder would need to be created manually, since the AD admin did not have the ability to set that up. am I suppose to somehow make the AD admin the admin of the OD server, and how would I go about doing that? Also:in the managing preferences section it mentions that I can add AD users to OD groups through the user selection tool, however in the selection tool the AD domain is not in the drop down menu, how do i get it there? (this could be due to the fact that WGM is not authenticated to AD and when I attempt to use the domain admins user name and password it tells me one of them is wrong, and I can verify that they are both correct, I also tried several combinations of possible AD admin short names) If anyone can help clear these up it would be much appreciated, I am new to OD, and I have been working on this server for more than a week as I have been attempting to learn it and integrate it with our preexisting AD services)