The answer to Issue 5 is the following:

 

<wsp:MessagePredicate wsp:Usage="wsp:Required"

         xmlns:it="uri:isssue5/types"

         xmlns:iw="uri:isssue5/wsdl">

 

         wsp:GetBody(.)/iw:reqMsg/it:something > 4

</wsp:MessagePredicate>

 

Since this quiz involves different problem domains I’ve decided to split the explanation into 4 different postings: