Pool wall rusting after only 6 years

We have a Colosseum 30' round AG 52" high pool. It's about 6 years old and this year we noticed rust stains on the outside of the walls. It appears the walls are rusting from the inside out. Pictures at http://www.flickr.com/photos/2574780...7624625355825/ When I run my hand on the liner from inside the pool (under water) I can feel rust behind the liner throughout the pool at all water levels.

I'm convinced this is caused by water getting behind the liner by way of the openings between the beaded (J?) track holders (20 of them on top of the pool wall). I think the chlorinated water getting behind the liner. There are pin holes where I can see the liner through the wall, and when the kids swim, water oozes through these pin holes.

We had one AG installer (only one we could find) who claims the liner was installed incorrectly, room behind liner and wall that allows condensation. I don't buy that theory.

1) Anyone heard of this problem with these pools (or bead liners pools)? The manual still shows this type of installation which I'm surprised at. See manual at http://www.strongpoolsandspas.com/in...ile.php?id=101

2) I'd like to replace the beaded liner with an overlap liner to prevent this problem. Is that possible?

3) anyone know of Minneapolis based installer who can be trusted?

Thank you for your help!!