Resource Assignment based on Virtual Server?

Hey all,

I have two virtual servers that are associated with the same access policy and need to assign an IP pool based on the virtual server that the user connected to. In my resource assignment, I'm using the following expression to make the decision:

expr { [mcget {session.server.listener.name}] == "/Common/VSTest-01"  }

The session variable appears to match correctly in the logs, but it throws the following error in the access logs:

Rule evaluation failed with error: syntax error in expression " [mcget {session.server.listener.name}] == /Common/VSTest-...": unexpected operator /

It seems to not like something about the "/" character in the string. I've tried using the escape character "\" before each "/" with the same result.

I've also tried changing the operator to "contains" and dropping the "/Common/" portion, but end up with this error:

Rule evaluation failed with error: syntax error in expression " [mcget {session.server.listener.name}] contains VSTest-...": variable references require preceding $

Any ideas what I'm doing wrong? I feel as though I've tried every combination with no success.