Payment modules not showing up

I have installed several payment modules, and none of them want to show up when checking out. All the of modules that came with the software appear and disappear like they are supposed to (when activated and deactivated). The new ones (Versign and Payflow) show up in admin, but not on the checkout page. It has to be something I did...but what??

I have been at this for over a week, and have tried almost everything. Anyone have any ideas for me to try. Thanks!