Booting a Precision 340 from Network

Hello,

We are looking for a way to boot a Precision 340 from our network.  On our older Optiplex GX machines it was always in the BIOS under Boot Sequence.  You could configure PXE to be the first boot device and off you go.  On the Precision machines we have found "Wake On Lan", but this only powers up the machine and boots from specified local drive.  Under Security in the BIOS we found "PXE BIS Default Policy" and set to "accept".  We still had no luck. 

Any ideas greatly appreciated!

Thanks

Chris