[CentOS] hostname not being picked up by DHCP

Hi - I am using the CentOS v5 desktop installation and am setting up a new lab for our engineering department. Initially I computers got their IP addresses and computer names from the DHCP process and the computer were getting the info from the dynamic pool. These name would be d-23-76.mnsu.edu, where the d stood for dynamic and 23-76 refered the IP address of xx.xx.23.76. The computer hostname would show up as d-23-76. I did not want the computers to get different IP address so I put the computers onto our DHCP table as manual DHCP clients by assigning a name and mac address to an IP address. Now the computers get the correct IP address but the hostname is localhost.

How can I get the correct name for hostname from DHCP?