Multiple IP addresses on two subnets


I have had OS X happy with 6 or 7 addresses on a single subnet and apache has 5 different virtual hosts and it was working great. However, now I have OS X setup with its primary address on one subnet and its secondary addresses on a different subnet and it doesn't seem to work. If I add the addresses after the machine has booted via ifconfig, it works fine. But, if the addresses are added via a script at boot time, the machine won't send traffic to or from any of it's addresses.

Any thoughts are greatly appreciated.

G4 with 2 450 processors
256 MB
30 GB Drive