I have a proprietary build system that uses an XML file to store version information in Perforce. We are moving to TeamCity, but want to retain this file. In my system, I update the XML file and submit it, then start the sync using the changelist of the XML checkin. In TeamCity, using agent side VCS, I can do this as a step in the build process but the changelist used for the build is now out of sync with the version file. What I would like to do is get the TeamCity generated build number, use it to update my XML file in Perforce, and then let TeamCity do the sync using my new changelist. Is it possible to write a plugin that will allow me to do this?