2560x1600 display issue. (x11?, nvidia 8800 GTS, hdmi, dvi-d, Dell U3011)

[Linuxguy123]

I received the Dell U3011 monitor today, which has a native display
resolution of 2560x1600.

I have an HP HDX9494 with an Nvidia Geforce 8800 GTS video card in it
that I am using to drive it.

The user manual for the U3011 is here
http://support.dell.com/support/edocs/MONITORS/U3011/en/ug/about.htm

The specs for the HDX9494 is here
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01490775&tmp_task=prodinfoCategory&lc=en&dlc=en&cc=us&os=2100&product=3747924&sw_lang=

Info on the Geforce 8800 GTS is here
http://www.nvidia.com/page/geforce_8800.html
http://www.nvidia.com/page/8800_tech_specs.html

The problem is that I can't get the laptop to HDX9494 to drive the U3011
at 2560x1600.

The U3011 has several inputs, HDMI, DisplayPort, DVI (Dual link) and
VGA.

According to the manual, the "highest preset resolution" of the monitor
when using the HDMI input is 1920x1600 @ 60 Hz.  The "highest preset
resolution" is 2560x1600 for DVI and DisplayPort inputs.

The HDX laptop does not have a DVI or DisplayPort output.  It does have
an HDMI port.

According to the GF8800 documentation, it has two dual link DVI ports
that support 2560x1600.

The HDMI wiki tells me that HDMI 1.3 should support 1560x1600@ 24 bits
at 75Hz.  HDMI 1.3 was released in 2006 and the HDX was built in 2008.
http://en.wikipedia.org/wiki/HDMI

When I connect the HDX to the U3011 HDMI port using a High Speed HDMI
cable, the maximum resolution I am able to select from the configuration
software is 1920 x 1200.

When I connect the HDX to the U3011 DVI port using a High Speed HDMI
cable and a dual link HDMI to DVI adapter, the maximum resolution I am
able to select from the configuration software is 1600 x 1200 

I have tried this with both the proprietary nvidia driver and the
nouveau driver.

I have tried manually editing the xorg.conf file with various modelines
to no avail.

When I run the nvidia-setting software and look at the properties of the
display, it shows a dual link connection for the built in 1680x1050
display and a single link connection for the HDMI device.

How do I get my HDX to drive the U3011 at 2560x1600 ?

Is this a hardware problem or a software problem ?

Does the nouveau driver use the xorg.conf file the way the proprietary
driver does, ie does it use modelines ?

Thanks !