Load balancing home dirs across multiple XServes

Our setup: 4 XServes acting as AFP and SMB file servers. 5 XServe RAIDs for storage 1 XServe acting as Primary Metadata Controller and Open Directory replica 1 XServe for Open Directory server and Secondary Metadata Controller 2 QLogic 5200 fiber channel switches to interconnect above 1 Foundry - ServerIronGT load balancer to front end the 4 XServe file servers Mac OSX server 10.4.8 and XSAN 1.4.1 Home dirs stored on an XSan volume The intent is to store mobile home dirs for about 400 simultaneously connected clients with failover in case one file server goes down. Client Macs can "Go, Connect to server" and put in the DNS name of the VIP for the load balancer, get randomly connected to one of the 4 file servers, login, and mount disks. But my problem is user network home directories. In Workgroup Manager if I specify any one of the 4 file servers as the one holding a particular user's home directory, then only that server is used when they connect, ie connections are not load balanced across the 4 servers. If I instead specify the VIP of the load balancer as holding the home dir, then users get a one in 4 chance of connecting to the same server. Otherwise they cannot see their home dir at all. So I think that somehow I need to be able to specify that a user's home dir lives on ALL FOUR of the file servers. But there's no way to do that. Suggestions? Anybody get something like this working? Thanks in advance for your replies.