Different header.php for different domain names

I’ve got an issue with a client’s existing WP install. He’s got a .net as well as a .ca and the client wants it when you go to the .ca it pulls up a different header or just logo graphic that has a Canadian Maple Leaf on it. About all. It’s on v3.4.2 however, because it’s such an old DB that it if I try to use WPML, I can’t because of the age of the DB. So I can only use subdomains, which won’t work here. Will anything?