Universal Anchor System UAS for Child Car Seats

I have a 2002 Ford Expedition Eddie Bauer Limited with 4 captains seats. I have 2 young girls that need to be in child safety seats. When I install either the base for the baby's rear facing seat or the forward facing toddler seat the belts do not cooperate. The seat belt angles are out of whack and not only make it very difficult to secure the seat but it does not look or feel safe when installed. The belts angle forward too far when they are against the stops and cause the nylon belt to bunch where it goes through the sliding male end of the belt assembly. I do not want to modify these components for obvious safety reasons but wondered if there were any good suggestions out there.
When I bought the truck, I assumed it would have the UAS (Universal Anchor System) for installing children's car seats but it does not. I have considered replacing the seats with a more recent model with UAS but they have custom upholstery and being a 2002, it is the last of that series and I don't know if an 03 and up seat would fit anyway. My seats are equipped with the tether anchors straps but no UAS anchors.
I have spoken to Ford's customer service and they simply told me that I am S.O.L. I have also spoken to the dealership who gave mw a similar response. I will not settle for "...live with it!". This is my children"s safety!
Has anyone else had this poblem and/or know of a solution?

Briefly: I want UAS anchors in my 2nd row captain's seats to accomodate my children's car seats because the stock seat belts do not fit well.

Thank you for any help you can offer.

Can you post up pictures?