Here is something I thought up that may or may not work. I'm going to try it unless anyone has already proven it useless. The idea is simply a block machined to fit over the forms with a lip to extend over the strips. You put it in place so it presses down on the strip and presses sideways at the same time, and then you take a clamp and apply pressure to the end of the wood dowel which presses on the form to hold it in place. If enough pressure can be achieved this way it should stay put and hold the strip from top and side. ...or it may just pop off and prove me foolish! Nothing really new here except the idea of the wood dowel sticking through the clamping caul so it can have force to hold it in place.

Hopefully this link will take you to the image. I can never get Shutterfly images to post here.

http://im1.shutterfly.com/media/47a2db22b3127ccef052507196d900000030O08IcuXLJs3aA9vPhw/cC/f%3D0/ps%3D50/r%3D0/rx%3D720/ry%3D480/