I never use milk powder in mine. And oatbran on its own should be fine. I got some nice wheatbran from the Dukan shop by mailorder. It was cheap and a lot, so after several weeks I'm only half way through it. I add just a little more baking powder than in the recipe, use a mixture of yogurt, quark and milk. I also got a nice result by separating the eggs and beating them up to a soft peak stage then cutting into the rest of the mix gently with a metal spoon. this was suggested somewhere on the threads and it seems to be good.
the other ingredients are fairly flexible anyway, so I just use a good tablespoon or so of the quark and yogurt.