It's always nice when after a struggle something finally goes right...today was one of those days. After a few attempts at creating a caching server for workstation server and builds over a number of weeks (using internal MS technology...currently). I finally managed to get the crucial component working today, this should mean being able to use local images to create new workstation builds rather than dragging the files down from a Redmond based server each time (which can take many hours).  The solution was in the help file for a change, but not in the logical place (IMO)...anyway I'll be re-imaging my Laptop with the latest Vista builds (looking good so far) and creating Servers more frequently from now on.