After adding the registry key, I can now use commercial skip - Thanks Andy.
However, I am finding this version to be very unstable. If I freshly boot, all is good, however, if I leave the MCE box on for a day and then access a show that has no commercial skip XML file, I am not prompted whether to create one. If I kill all of the EH* services and restart mediacenter (no reboot), I then get prompted again. It is like the service just stops working. I have looked for a log in %PUBLIC% that may be of help, but nothing is jumping out at me.