Ram Van seat covers

I bought a 2003 Ram Van 1500 recently and I'd like to get seat covers to protect the vinyl on the bucket seats. Every bucket seat cover I've looked at has a flap that is to be pulled through the gap between the seat and the seat back. In my truck there is no such gap, however. There is a cage behind the seats, so they don't recline and they don't fold down. The only adjustment available is that they can be pulled forward. Does anyone have any ideas on where I could obtain covers for seats like this? Clark