I recently had to sync two svn repositories, one local and one remote repository. Both are running Visual SVN Server 2.5.2 (with Apache Subversion 1.7) and the local repository should be used as mirror for the remote repository.
First you have to create a new (local) repository and then initialize it:
svnsync init https://localhost/svn/Repository https://remoteServer/svn/Repository
After that you can start the synchronization:
svnsync sync https://localhost/svn/Repository https://remoteServer/svn/Repository
If you get an error that you have to set the “pre-revprop-change-hook” correctly in your repository, just open the Visual SVN Console and add a few blank lines to this hook. And you will see it works fine!