Alteon AD4 load balancing

Can anyone help configure two AD4’s with Active / Active and load balancing web servers with persistence ?
Config is too long to post but I have tried using various metrics and pbind client ip and the problem is that
When one of the server http daemons is stopped for maintenance the end user gets a server ip error unless a clear is issued from the AD4.
The session will eventually timeout and end user is routed to the other webserver. Can this be configured so the end user gets redirected immediately to the other server or gets a session timeout error immediately ?