Brilliant, thanks for that.Just making sure ;)
They play just outside the main ground, apparently their changing rooms are actually inside the main stadium itself.
http://www.borussia.de/english/club/stadium/location.html?print=??type=2
http://www.borussia.de/english/team/academy/youth.html
Edit: Pics here - http://www.stadionfreund.de/berichte2013/0526-fohlenplatz.html