There are two different graphics driver for US15W GMA 500 Graphics Controller. Most customers do start with the GMA Driver from Microsoft which primary is written and supported from the Intel Mobile Group. To support your own display configuration, you will need the Intel Embedded Graphics Driver.
You will find the most accurate GMA500 driver here: http://downloadcenter.intel.com/Product_Filter.aspx?ProductID=3180&lang=eng Download and install the driver directly on the target.
On Robin, you will get the problem that you have a black screen after driver installation. This is due the fact that GMA by default will use DVO as the primary Output. You can switch this by using the following 2 Hotkeys:
To support your own display configuration, you will find more information about IEGD generation and configuration here: IEGD
You can download an IEGD Driver Sample which Supports Displays with EDID information here (for WinXP): http://files.toradex.com/X86/Software/XP/XP_WR_L_IEGD_10_1.zip
The Configuration File to rebuild the Toradex Sample driver can be download here (for WinXP): http://files.toradex.com/X86/Software/XP/XP_WR_L_IEGD_10_1_Config.zip