Joy, show me a picture.

I'm deep into it body work lately:
http://www.benplace.com/gerry2.htm

Understand one thing, seam rust as no real answer unless you replace the
seam. But in some ways, a seam can't be replace :-)

Seam rust start from the inside first and make is way out, so when you see
rust outside the damage is way more extensive inside.

You can understand a lot if you carefully look at a page i did last year:
http://www.benplace.com/panel1.htm

So bring the pictures. Post here if you want, it can be helpful for others.

Cheers, Ben
http://www.benplace.com/vw2.htm