Volkswagon vanagon

I recently purchased a Volkswagon Vanagon. I have 3 kids, 3,5,7. My question is about the 2 rearfacing seats I have. One is behind the passenger seat the other behind the driver. I was told that because they are rear facing they do not need shoulder straps. Is this true? Should I have shoulder belts installed too? I have also read that my 5 and 7 year olds booster seats can not be put in rear facing seats. I know the turbo booster with the attatched back and headrest can not be put ther per the manufactures instructions. One is the small, light, inexpensive seat with the green cover - the name escapes now and the seat is with the child - no back or head rest (which the vanagon does have-headrests for everyone.) Can that booster be used with the rearfacing lap belt? Could it be used if I have shoulder belts installed in the rear facing spots? My 7 yr. old is 60 pounds so when carpooling he could technically ride in the rear facing seat alone with another child over 60 punds in the otherrear seat, but I planned on keeping them in boosters until 80 pounds and I want some info. to back up a decision of this importance. The rear bench has 3 lap belts. I am having 2 shoulder belts installed in the rear and I will have my kids ride 3 in a row with the 5 point harness in the middle lap space for daily riding. Long winded but wanted to get all of the details in. Thank you.

Not very familiar with Vanagon-

Some general rules-

No child restraint (boosters included) is recommended to be used in any vehicle seat that faces the rear. If the owner's manual for the vehicle allows children to be in that seat, then you should follow their recommendations for weight and height limits (if any).

Shoulder belts improve safety considerably in any seating position. Since rear-end crashes are much less common and severe, you could argue that they are not as critical in a rear-facing vehicle seat. Boosters are generally not recommended to be used unless a lap+shoulder belt is available.

It sounds like you may be a bit restricted in seating positions. In your situation, I would highly recommend a visit to an experienced technician. You may use the resources at http://www.seatcheck.net to find one in your area.

In the mean time, having shoulder belts installed for the rear seating sounds like it will be the best action for you.