You cannot do both diets together, It would be dangerous as you are getting exactly what you need on CD.
I was trying Xenical before I started on CD and was told by both my Dr and CDC that I couldn`t do both. I`m doing 810 plan which involves an evening meal and had asked if I could take the Xenical with that.
Yes, absolutely no point in doing the two together as Cambridge is already low fat. Besides, there would also be a problem with some of the fat soluble vitamins in the products not being properly absorbed.