the question is a bit vague.
If you want ACE to force some traffic to go to a specific server, you have to first create a class-map to catch the traffic, then create a serverfarm with a single rserver which is the destination where you want to send the traffic.
Configure the serverfarm in transparent mode to avoid doing any nating and then associate serverfarm and class-map in a policy that you can then configure on inbound interface.
Gilles.