Screen resolution in KDE without monitor connected.

Hi, here is the task. File server under OpenSUSE 12.2 with KDE. Managed via VNC. If server starts with monitor connected everything just perfect, resolution appropriate, as it was saved by default. BUT! The task is to provide the possibility of switching on and switching off the server without any monitors connected. And here is the general problem. Without monitor X-s starts with resolution 1024x768 and doesn’t allow to make it higher. Can any one know how to solve this problem?