Form perforated sheet metal

Hi, I'm trying to create a fan grill using a form tool.

I've sketched up the perforated sheet metal and a form tool... the problem is when I try to use the form tool, it forms the sheet metal, but the perforations just turn into a solid mass. Any suggestions?

I've included both the model as it stands plus the form tool for reference.

Thanks

James

SolidworksSheet Metal