video out with suse 9.3

hi list, I have installed the new SuSE 9.3 on a dell latitude 840c. I can use the external beamer upto a resolution of 1024x768. The display can more but the external video gets initialised with the max resolution of the display, causing havoc. When i have any higher resolution that 1024x768 in the list it does not work. strangely when i switch size there is no change on the beamer display. i guess they use the virtual display instead of the real one. is this a configuration option ? any hints ? re, walter