Hi,
In ACE, you will have to set the idle timer via a connection type parameter map and apply it to the class, inside the multi-match policy:
cdn-ace-2/bermicha(config)# parameter-map type connection TIMER
cdn-ace-2/bermicha(config-parammap-conn)# set timeout inactivity ?
<0-3217203> Inactivity timeout (default TCP 3600, UDP 120, ICMP 2)
cdn-ace-2/bermicha(config-parammap-conn)# set timeout inactivity
...
cdn-ace-2/bermicha(config)# policy-map multi-match POL
cdn-ace-2/bermicha(config-pmap)# class NAT_46
cdn-ace-2/bermicha(config-pmap-c)# connection ?
advanced-options Specify connection advanced parameters
cdn-ace-2/bermicha(config-pmap-c)# connection advanced-options TIMER
cdn-ace-2/bermicha(config-pmap-c)#
Michael