Hi Heiner, actually ctrl does not have any special effect when clicking on the view buttons - it's just a second click (either ctrl held down or not, it doesn't matter) on the already activated view button that will switch it back and forth from the reverse view.

Check out here for what script to put in for the "command" part of the shortcut key in order to jump directly to a particular view:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3808.2

- Michael