Ok, doing some more digging I found this article discussing External Directories which seems to be the alternative for JBoss 5.1.0.
http://community.jboss.org/wiki/ExternalDirectories
Problem is, when I add this to the profile.xml file, I still cannot access the generated file using a URL.
<property name="bootstrapURI">${jboss.server.home.url}conf/jboss-service.xml</property>
<property name="deployersURI">${jboss.server.home.url}deployers</property>
<property name="applicationURIs">
<list elementClass="java.net.URI">
<value>${jboss.server.home.url}deploy</value>
<value>${jboss.server.home.url}virtualDirectory/reporting/output</value>
<value>${jboss.server.home.url}virtualDirectory/app/output</value>
I still get a HTTP 404. I can see the file is being created in the directory specified but I can't seem to access it via URL.