ISP PPPoE Unnumbered IP, with Routed Subnet 2 IP

Hello al

I have a customer that has an Unnumbered IP with a routed Subnet with 2 IP's.

81.173.64.xxx (Unnumbered IP)

81.173.73.xxx (2 IP's)

I have a Fortigate 51E with Firmware v6.0.4 build0231 (GA)

Now i got the Unnumbered IP running on the WAN and i can have all the Networks working on that IP.

The customer wants his office to go out in 1 of the routed subnet IP's and his Customers on the other Routed Subnet IP.

I put both routed subnet ip's (each one separate) in the "Policy & Objects --> IP Pool and put them on overload.

Than i tried to go to "Policy & Objects --> IPv4 Policy --> (rule) Office to WAN --> Firewall/Network options --> IP Pool configuration --> Use Dynamic IP Pool.

When i put the Office IP there that i configured in the IP Pool, i can't get on the internet. When ik Ping to 8.8.8.8 i get no replay.

Can Anybody help met with this?

Thanx

Gidion