I am looking for a homade recipe for the Wilton Cake Release. All the recipes I have seen so far are oil with flour or oil, shortening and flour, but the ingredients on the bottle say soy oil and Corn Starch. Does anyone have a homade recipe using soy oil and cornstarch?

You probably will never find an exact recipe. Corn starch can be added - is suggested in areas of high humidity weather. And one can always sub soy oil for the vegetable oil most recipes call for.
But the recipes you have already seen are just as good. They work the same way. Just beat/mix it until it is light like whipped cream and store in a air-tight container.,

I make my own cake release all the time. It is even amounts of vegetable oil, shortening and flour. Most of the time I use 1 cup of each.

I've never heard of one using soy oil and corn starch. Hope you find it.