Don't know how this is going to work. How are they going to explain the presence of the palantir? Did he tack that on to the TTT EE, and he's assuming we'll have seen that before we see RoTK?
Peter may cut out any scenes involving the Isengard/Orthanc Palantir. Or he may do some fancing editing to make it look he's using the one in "Minas Anor" ;-) at the appropriate time instead.
Still, I think it is a very dissappointing way to treat Saruman, who's been built up as a villain with tremendous presence in two films and projected into the third.