diff --git a/koan/app.py b/koan/app.py
index 23ab5f3..5352f7d 100755
--- a/koan/app.py
+++ b/koan/app.py
@@ -1495,7 +1495,7 @@ class Koan:
                         raise InfoException, "LVM creation failed"
 
                 # return partition location
-                return "/dev/mapper/%s-%s" % (location,name)
+                return "/dev/mapper/%s-%s" % (location,name.replace('-','--'))
             else:
                 raise InfoException, "volume group [%s] needs %s GB free space." % virt_s