When I first got Tanner as a kitten I tried to give him the Iams kitten food and he just wouldn't have anything to do with it. I then switched to Science diet nature's best kitten food and he would eat it. Unfortunately Emily loved it also and wasn't so concerned with her "girlish" figure so she gained some weight off it.

I finally found one that they both will eat (and it is actually made in Canada so you shouldn't have problems getting it). They are now on Nature's Recipe Optimum Maintenance Feline available at Pet Smart. For some reason this one seems to be doing the trick for now...

Good luck with Tilly.