Build-Specific variable for Maven2 version

After building in Bamboo, we do a manual job by tagging in SVN with a tag corresponding to the Maven2 version (tagging with 2.0.5 if the version in Maven2 pom.xml is <version>2.0.5</version>). We would like to automate this process, and are looking at trying out the Bamboo Tagger Plugin (http://confluence.atlassian.com/display/BAMEXT/Bamboo+Tagger+plugin). As the Tagger Plugin can use Build-specific variables, it would be really useful is we can get the version from maven, similar to how you get the revision number from SVN (custom.svn.revision.number).