replacing lap-only belts with 3-pt belts

I've been doing some reading on this group, and found a lot of good information, but still have a couple of specific questions:

We have an older conversion van, with lap-only belts in the rear (2 captain's chairs and a 3-seat bench). While this has worked for kids in their 5-pt car seats, it won't work for booster seats.

Does anyone know whether it is possible to retrofit the 2 captain's and/or the outer two bench seats with 3-pt belts? Or should we be looking for a different vehicle? If it can be done, who does it?

I also had a question about rear-facing the captain's chairs. They are swivel and have 2 position locks - forward and reverse, both are equally supported within the seat mount.
I read somewhere that booster seats are intended to be forward facing only; is that because they have not been tested in rear-facing seats, or is there something inherently unsafe about traveling in a rear-facing seat? Perhaps the seat posts are designed to withstand only the weight of the seat and not seat + occupant (occupant's weight would be transferred to the seat instead of the seat belt if traveling rear-facing)? I would have thought that rear-facing would be safer, so info to the contrary would be greatly appreciated.

You should contact the vehicle manufacturer about modifying your seatbelts. I know some can be modified, but it's generally very expensive and depending on the condition of your vehicle, relative cost to replace, etc, it might end being cheaper to buy a new car


Child restraints are not allowed to be installed in a rear-facing vehicle seat, per the manual. We don't know if it's because they were tested that way and failed, or not tested that way at all.

What are the ages/weights/heights of your children?