Starteam to X migration? (where X is one of: svn/git/hg/bzr ...)

Question

Is there a tool that can migrate Starteam to svn or git or any other modern/decent source control system?

I'm thinking of something along the lines of how git-svn works; allowing you to use git to pull from an svn repository.

Something that can import a StarTeam repository and convert it to an svn repository, but also keep pulling from Starteam and adding to svn.

Hell, even a "starteam to cvs" tool would be fine, as long as I can keep pulling from the starteam repo after the initial migration.