I have an application where several sites works with one common back end. That is implemented by having one ear file with multiple war files, one per each site with virtual-host and context-path set in jboss-web.xml.
If I add schema information to application.xml then the ear fails to deploy, it requires context-path to be set for each web module and each has to be unique, i.e. I can't set all to /. It doesn't take into account that those web modules use different virtual host.
The only workaround I've found so far is to not have any schema information in the file, hence it's not validated.