Windows 7: Add New Screen Resolutions is disabled

Hi

I am hoping someone can help me.

I have just bought at Dell XPS 17 - Windows 7 Professional 64 bit

3G Nvidia GE Force GT 555M with Optimus Video Card.

I need to add a New Screen Resolution 1014 x 675, but unfortunately the Add New Resolution options is disabled.

I have contacted NVIDIA and loaded a new driver 301.42-notebook-Windows 7-winvista-64bit-international-whql, which increased the options in the Nvidia Control Panel, but did not allow me to Add a new Resolution.

The Monitor Asset Information is - Generic PnP Monitor (more details attached)

A Screen print of what I am seeing in the Nvidia Control Panel is attached.

The Nvidia Support team is basically telling me the Screen Resolutions have been locked down by the EDID policy on the monitor (which I don't really understand).

Has anyone got any ideas as to what could do to create the New Screen Resolutions?

Any help would be greatly appreciated.

Thanks
Jo