well jsut my quick thinking (well it took me 2 hours thinking), maybe you can cut the belt and attach it and then reglue the cut. Unless the belt is bigger or smaller than Sentry's waist, then out a "section" of the belt and adjust it to the right size. Hope it helps
all I need now is a sentry and a batman hush head
To fit it onto Sentry:boil the belt again and let it get soft and very flexible then slide it onto Sentry(you may want to remove Sentry's legs first)