mechanical strenght of mono-comp. polyurethanic foam?

[sbrofio]

Hi, I'm going to build the background of my orchidarium. The sizes are 150 cm tall (59 in) x 105 cm large (41 inches).

I'm wondering about the mechanical strenght/solidity of a 130x105x10 cm (51x41x4 inches) panel of foam.
I've got 20% little (diploprora, amesiella) plants, 70% medium (botanic phals and similar) plants and 1 big Vanda (4/5 kg - 8/10 pounds) I'd like to hang to the wall.

So the question is: does a nail put in a foam-wall resist to the weight of the big Vanda?

I'm not sure but I think the answer is no, so I'm thinking about build a skeleton of metallic net - hydraulic hoses - metallic net, like a sandwich. As nails, I'll use long piece of iron wire linked to the front and rear net.

What do you think about this idea?

example of the inox steel net http://www.wire-mesh-fences.com/phot...tone_works.jpg

something similar to what I want to do http://img683.imageshack.us/img683/1265/img0179qv.jpg