Fixings onto foam backed metal

[glocko]

I need to fix a shelf up in a catering kitchen.
The only problem is the wall is a thin metal with an insulating foam backing of about two inches thick.
The shelf will be stainless steel and carrying a little bit of weight (About 10 lb over a 3foot width.)
There is no access to the rear of the wall.
What fixings would be best for the job?
Thanks chaps

 

[Jasonb]

Possibly self tapping screws or rivnuts which will take machine screws.

Jason

 

[Hitachimad]

Some nice stainless self tappers, or stainless Tek screws (self drillers)

 

[Tim 77]

I always use stainless self tappers when fixing to silmilar walls in food factorys, nothing's fell down yet.