having trouble trimming a surface.

Im currently doing a simple project, trying to perforate a plate with a picture - where I made a heightfield and the perforations are polygons. Currently, with previous help from this forum, I am at the stage where I have a huge set of hexagons (not circles) with faces hovering over a surface (the surface which i want to puncture with the polygon pattern), now I also know how to project the hexagons on the surface. But I cant get it to trim.
So - approx 10 000 polygon pattern projected onto a single surface and I can't trim.
I tried the suggestions from the Surface trim workflow thread and still didnt get it working.

The trimnotworking file is the definition.
The maitea file is the hmm, other (basepicture, hidden), file.

Thanks in advance :)