We've just traveled overseas with our Combi Cocorro and we've run into a serious issue.
I'm installing it rear facing. The car we are using does not have latch, the back seat has three shoulder belts (no lap-belt only seats) that DO NOT LOCK.
When you pull the belt all the way out and then release it, it doesn't lock the way I'm used to belts working in any other car I've used. It only locks if pulled quickly, but I know that is not safe for a car seat install. It needs to be pre-crash locked.

I can't find the manual and this car isn't sold in America so I'm having no luck online on English language sites, so frankly I'm panicking. Help? It's a BMW Station Wagon, 1999, 530D Touring.