How can I add an application to the Open With menu?

I have Bridge CS4.

Right now the default for CRW files is that they open in Photoshop. When I right click the files "Firefox" and "hugin" show as options in Open With. I would like to add another app to that Open With menu. Photomatix, specifically. How can I do this? How is firefox and hugin even in that list? I just want to be able to open images straight from bridge into Photomatix.

Thanks