Invalid root directory if concrete is symbolic link

[a3020]

I'm using a symbolic link for the /concrete folder. Using the build tool (php i18.php --package=...) I get the following error: /www/test.com is not the valid concrete5 web root directory (the version file does not exist).

Is there a trick or should I modify the script so it loads the core from another folder (eg. /www/c5721/concrete)?