Looking at the picture, I think jrd22 has the right idea--put the gasket between the side of the upper insulation and the side of the fridge, rather than under the lip of the lid. There appears to be a gap there, and you'll get your seal without interfering with the lid closing.
2000 Beneteau 331
Northern Chesapeake Bay
Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright