I was in the same predicament over year ago but 'nothing' seemed to work in the conversion of mice to rats until I started using 'dirty mouse bedding' and tough love. At least w/ dirty mouse bedding, you don't have to worry about wasting a new mouse each time. Just a thought....Good luck!
What the heck is "dirty mouse bedding," where do I get it, and what do I do with it once I have it? Also, what do you mean by tough love?