I'd get a few pastel females, raise them up and plug in a het caramel male into them. You'd end up with pastels poss het caramels. Raise up those possible het females and breed the caramel male back to them. The problem with a het caramel female, is deciding which possible het pastel male to breed to her.

Or you could buy a caramel female, breed you pastel male to that, and end up with 100% hets. Then you'd breed one of the pastel sons back to her.