With PortServer TS products, only root can access the Web, meaning there is no option to use radius to authenticate via HTTP/HTTPS.
Also, if I'm reading the following correctly, the user should not exist on the PortServer unit for SSH connectivity:
http://knowledge.digi.com/articles/Knowledge_Base_Article/Using-Radius-to-control-user-access-levels-on-the-Portserver-TS