Anytime you post a question, it is very helpful to get as much details as possible. For example, you are not stating which OS you are having problems with. You also do not mention if this is at the OS level or at the BIOS level duing PXE booting for imaging
Assuming you are running Windows 7/x64, there are updted drivers for the NIC and the BIOS. You can updte directly frmo the web, starting at www.hp.com/go/support or update with HP Softpaq Download Manager (www.hp.com/go/sdm). Once updated, you should be able to set the speed of the nic in Windows Device Manager, nic driver property settings
If you still have issues after updates, then it might be an issue with the drivers and I suggest you open a case with HP Support. You can access support online at
http://h20566.www2.hp.com/portal/site/hpsc/public/scm
then select "get help from HP" and "submit or manage support cases"