There's no app to lock apps in landscape mode yet
And I think it's better if this option is added to CSSU Features Configuration application.
It's insane to make an app for each feature for each app
The only think you need is add the program to transitions.ini, in thp_tweaks.
Example:

blacklist = mediaplayer osso-xterm worldclock image-viewer camera-ui

But you need to compile from gitorious (or wait for the update) to try this now