--- a/req.py	Thu Feb 04 13:17:26 2010 +0100
+++ b/req.py	Fri Feb 05 07:25:16 2010 +0100
@@ -341,7 +341,7 @@
         """return a string for floating point number according to instance's
         configuration
         """
-        if num:
+        if num is not None:
             return self.property_value('ui.float-format') % num
         return u''