I have Xdebug 2.1 installed, and running with PHP 5.2.13. It can successfully connect to multiple DBGP clients (i.e. the xdebug.remote_log shows communication
xdebug.remote_log
If php files are placed into symlink-folder then XDebug will operate with source folder path instead of symlink-folder path!
So to enable breakpoints you should configure path mappings in your ide for symlinked folders and files