The branch aware subversion repository does not appear to provide the repository revision in any meaningful way in situations where there is build that has not had changes.
This is bit problematic as we'd like to use the SVN revision as the build number, but it's not available from the repository at least when a new project is set up using repository where there have been no changes while the project has existed.
If there is another method for accessing the repository revision, I'd like to know.
The issue is that when the repostiory is first checked, we were getting the head revision of the repo and inferring the branch from it to create the initial changeset, but we should have been creating an initial changeset for all branches. Viinnie is working on this now. If you commit to that branch then it should pick up a changeset and the revision will be available. We should have a new beta available tomorrow with the above mentioned change.