PN port fetch/write port NO.

Hello everybody

I am working on Proface HMI "GP2500-TC11-24" linked to cpu S7-300 2PN/DP using ethernet communication.

I faced a problem that I MUST enter the PN fetch and write port No.......first time to hear about somthing like that 

after searching I found that I can find these two numbers if I use CP.

But I can not find it if using CPU ports.

any suggestions??????????