Balancer 2500 pepvpn tunnel reconnecting after dhcp reservation

HI all,

I have installed Balance 2500 for my customer, they use pepvpn with NAT mode and DHCP reservation.
Every time the new site up we reserved the IP add so only that store can use the ip.

The problem occurs when we reserved and apply the setting, all the pepvpn tunnel on that same IP segmen will be reset and reconnect. We are using fw 8.1.1 build 5006.

Does anyone have some solution ?..

Thanks before.