to follow up to myself this was in actual fact super easy, all i had to do was add
driverdisk --source=http://xxx.xxx.xxx.xxx./cobbler/ks_mirror/drivers/dd-RHEL4.img
to my kickstart template and it was away!
naturally that should read....
driverdisk --source=http://@@server@@/cobbler/ks_mirror/drivers/dd-RHEL4.img