http://www.w3.org/2006/07/13-ws-policy-minutes.html#action08

Section 3.4 of the PolicyAttachment document introduces an External Policy attachment mechanism that uses a domainExpression to refer to the policy subject. But there is little discussion ofwhat domain expressions can refer to.  Section 4.2 of the PolicyAttachment document gives an example of a domainExpression. First, this is a non-example as it says little about the domainExpression. In fact, it says less than the example at the end of 3.4. Second, there is no reason for this example to be separated from section 3.4.  My note, http://lists.w3.org/Archives/Public/public-ws-policy/2006Jul/0019.htmlsuggests domainExpression designs that allow a WSDL 1.1 definition, a http message or a JMS message to be referred to as a policy subject.  SUGGESTION 1: Remove section 4.2. It serves no purpose.  SUGGESTION 2: Add some discussion of domainExpressions using examples from my note above.  
All the best, Ashok