Port forwarding on HG659 help needed.

I am trying to forward 2 ports to a raspberrypi on the Huawei HG659. I set up the first one OK...

Mapping name raspberrypi

Application Webserver

Internal host raspberrypi_Ethernet

but when I try to forward the SSH port

Mapping name raspberrypi

Application SecureShellServer

Internal host raspberrypi_Ethernet

and go to save it I get the error message "The name of the port mapping is invalid"

I am a real noobie on this subject, appreciate any help.