--- /etc/univention/templates/files/etc/network/interfaces.orig	2012-05-21 12:54:56.000000000 +0200
+++ /etc/univention/templates/files/etc/network/interfaces	2012-05-21 12:55:52.000000000 +0200
@@ -75,7 +75,7 @@
 		for key,value in configRegistry.items():
 			if key.startswith('interfaces/%s/route/' % i):
 				if value.startswith('host ') or value.startswith('net '):
-					print 'up route add -%s dev %s' % (value, i)
+					print 'up route add -%s dev %s' % (value, i.replace('_', ':'))
 
 		for key,value in configRegistry.items():
 			if key.startswith('interfaces/%s/options/' % i):