I personaly have no experience switching animals over from baby food to crested gecko diet. i Know Anthony has (it says so on his webpage) most of the information i have read says that you need to ease it over. so over a month or so perhaps add a little bit more and more of the gecko diet to the baby food until it is replaced fully. also i think the animal will start to eat it simply out of hunger. by no means am i a final word on this as like i have said i am only giving advice based on what i have heard. i know when i start to supply the gecko diet i am going to offer it every night. i think this will be helpfull in ensureing the animal has access to it during its feeding times. I have seen many people use those mini disposable sample cups that you get at a deli or baskin robins and simply throw them out after one or two uses. if you have only one or two animals it would probably be more efficient to keep a small dish that you clean regularly. anyways just my thoughts.
Also you might want to scour these forums for old posts on the issue as i am sure there are a few out there