I don't know if there is a way to do what you're asking, but here is a possible work-around if you can afford the real estate on your drawing sheet. Use a detail view of just the perforated metal surface (or whatever it is you want to illustrate) and set the detail view to Shaded or Shaded With Edges. It should only require a small circle to illustrate your point I would think...?
Use the the detail view title as a note to get your point across, i.e. 'NOTE: PERFORATED SHEET STEEL MATERIAL'. Or whatever suits...
How about using a sketch picture over the required area.
Maybe creating a sketch on the drawing to use as a cropping outline if required to make the image file.
Another thought is to try hatch.
Perhaps there's a hatch pattern available that's appropriate for your reguirement.
The way a lot of people show that on drawing is to add the perforations in a corner or a random splash of holes, rather then showing the entire part with holes.
You may want to check out this thread by Shaodun Lin
I ended up doing it the way that James suggested. Not really the best way to display, but it works for the project.
Thanks to all