PXE Boot across VLAN

Any help is much appreciated.

We have just deployed Altiris 7.1 (NS) in our environment for the first time.

Previously we used WDS and DT2010 and was able to PXEboot across VLANs just with the DHCP options set.

NS is on a separate VLAN from the DNS and DHCP servers.

I have set the DHCP option 66 (Boot server host name) with ip address of NS and DHCP option 67 with the Bootfile name as BStrap.0.

I am unable to boot from the other VLANs only from the VLAN that contains NS.

The network engineer refuses to add ip helper addresses to gateways. How can we PXE boot without IP helper addresses on the routers?

Bish