from my personal experience with WM, it seems to depend on whether the workout you have entered in your WM calendar was from a pre-loaded rotation or added in the "old fashion" way, one day at a time (before the rotation option had been activated. My numbers do not show up either for my November Cathe rotation, and I believe that SNM said that this was one of the many future upgrades they are working on right now... I guess it also has to do with your stats you enter in WM. If you enter states, it should take all the other data from their WM tables to personalize your calories burned, and other data, so it's not a flat "calories burned" for everyone but determined on an individual basis... If you haven't entered your weight, height, etc stats, it can't calculate any of the calories burned, etc...
You could always to a trial and go to December calendar, enter a workout the old way, mark it complete and see if it will calculate your calories burned at that time...
I have to agree that sometimes I can't believe the calories burned, but would like to think that if I am giving a w/o my 100% (like Nancy said) that I'd be close anyway! I also must take that number with a grain of salt, because as I would not consider myself an advanced exerciser yet, I do mostly intermediate and advanced workouts, but can rarely do them as published and find that I have to stop for breaks when I need them, therefore, even though the WM gives a total calories burned, that would assume you did everything, which I can't often profess... yet!
I guess that is the beauty (and a fault) of rolling out interactive upgrades (beta) that you don't get the whole package right off the bad like purchasing a complete program.... there are always going to be changes needed and wanted