Setting realm from called station id regex

Hello, I have some devices that report to radius accounting but do not do any authentication or authorization. For these sessions in accounting, I would like to set a realm based on the called station id. The called station id ends with a colon and the SSID. I thought I could write a simple regular expression for the ssid and set the realm. Here is what I have right now, but it does not seem to be working: DEFAULT Called-Station-Id =~ "myssid" Realm = "myrealm" Any help is greatly appreciated. Chris