Make it possible to use the Subversion revision number as the build number

Currently, I have three separate numbers that indicate the version of the software being built:

1) The Subversion revision number
2) The Bamboo build number
3) The application build number (which is held in a properties file that Bamboo updates on every build)

I want all of these to come from Subversion. This means that:

• Bamboo should obtain and hold the revision number when it does an 'svn up'
• Bamboo should use this as the build number
• Bamboo should (ideally by default) pass this number to Ant so that I can use it as a substitution value during the build.