Well it does not work as I expect. Standby GW is still standby:
GW2# cphaprob state
Cluster Mode: High Availability (Active Up) with IGMP Membership
ID Unique Address Assigned Load State Name
1 172.16.0.1 100% ACTIVE chkp-1
2 (local) 172.16.0.2 0% STANDBY chkp-2
GW2# clusterXL_admin up -p
Setting member to normal operation ...
Member current state is STANDBY
GW2# clusterXL_admin down
Setting member to administratively down state ...
Member current state is DOWN
GW2# clusterXL_admin up -p
Setting member to normal operation ...
Member current state is STANDBY
GW2# cphaprob state
Cluster Mode: High Availability (Active Up) with IGMP Membership
ID Unique Address Assigned Load State Name
1 172.16.0.1 100% ACTIVE chkp-1
2 (local) 172.16.0.2 0% STANDBY chkp-2