Help with websphere relevance for upgrade

I want to create a relevance to check if a copy of WebSphere needs to be upgraded.
Here is what I have tried:
((exists matches (regex “com.ibm.websphere.ND.v85”) of node value of attribute “id” of it) AND (node value of attribute “version” of it < “8.5.5009”) AND (node value of attribute “version” of it >= “8.5.5000”)) of xml documents of files ("/opt/IBM/WebSphere/AppServer/properties/version/installed.xml")
This does not work.

  1. What am I doing wrong?
  2. Where can I find documentation on how to parse xml files within BigFix relevance.