[CentOS] Centos 5.1 + beryl + 1440x900 -thanks!

Hi to all, maybe someone could help me out, I have installed beryl in centos
5 following directions on internet, configuring repos from fedora core 6 and
I successfully installed it but the problem I have apparently is that it
only works when my resolution is 1024x768 or less, I have a Toshiba
satellite p105-s6147 with a graphic card mobile intel 945gm/gu express. I
have problems too when I want to change resolution to 1440x900, the menu
doesn't show that option the max is 1280 or something like that, well I you
could open my eyes it will be much appreciated.

Thanks for all.

George from Uruguay.