I have a b1 installation fully updated (to b2 i assume since it was released a few days ago) running under vmware esxi 4.1.
I went to "Control Center \ Hardware \ Browse and configure hardware", selected the videocard "SVGA II adapter" and then "run config tool". In there, i selected as monitor "Flat panel 1280x768" and resolution "1280x768 24bpp". After that i restarted the PC, however the resolution before loging-in but also after the login was set to 1920x1440 instead.