Alfred, do you have the latest version of CSSU (PR 1.3.3.7-7 update available for Maemo 5 CSSU.), because there is now an option to switch on or off the 'orientation lock' via the menu. This might solve your problem, unless of course this what you are referring to already... (I haven't tried it mysef), as I have not got Extra test Repo loaded to install the game!
Before starting put phone into locked rotation via the applet.