leaking rear roof seam

[pcatterall]

my 2001 hitop has a leak along the rear roof seam. I have heard of several others with this problem, I have treated the visible rust but what is the best way to takle the leak?
Was going to try silicone sealant.
???
thanks for any hints

[AndyG]

NOT silicone sealer
But auto seam sealer

[MrMPuk]

Mark says fibreglass, I say Epoxy Resin.

[pcatterall]

Thanks guys, thats 3 alternatives to go for.
I thought auto seam stuff was more of a building seal, ie squidge the stuff in when the joint is being made. I suggested silicone my be better just to seal the exposed edge as the auto seam seal wasnt so good when exposed...correct me please.
Considering fibre glass epoxy; I guess the proper solution would be to remove a strip of paint right down the seam and cover with a strip of fibreglass material and some coats of epoxy.
I think I will try the seam seal idea first and see if it works. I note that on the roof this seam forms a hollow along which rain will run and gather, I will degrease this and give it a light sand for adhesion then fill it with sealant.
Some more ideas about sealant welcome.
Fibre glass/epoxy if this fails!!
Van is being converted to camper van complete with roof insulation and headlining so essential no leaks!!
Thanks guys... helpful as ever
Regards

[jace]

silicone eats into your paint letting the rust get a foothold