Today I taped the seems in the Durock, using the special cement board fiberglass tape.  I say special because its apparntly not the same stuff that is used for installing sheetrock, which of course meant that I had to go buy a whole new roll of the stuff.  The cement board stuff is Alkali resistant to protect it from the cement based thinset.  The general process was acutaly pretty easy, although I did end getting more thinset on the floor, than on the joints when trying to do the upper corner, but I was smart enough to put some tar paper down before hand.   Therefore the only downside was the thinset getting on my feet.  This picture looks a little odd, because the thinset is half dried, so part of it is light gray, and part is dark gray.