diff --git a/src/Spring/Spring.Data.NHibernate/Data/NHibernate/DelegatingLocalSessionFactoryObject.cs b/src/Spring/Spring.Data.NHibernate/Data/NHibernate/DelegatingLocalSessionFactoryObject.cs
index 03e68234..c559a151 100644
--- a/src/Spring/Spring.Data.NHibernate/Data/NHibernate/DelegatingLocalSessionFactoryObject.cs
+++ b/src/Spring/Spring.Data.NHibernate/Data/NHibernate/DelegatingLocalSessionFactoryObject.cs
@@ -40,12 +40,20 @@ namespace Spring.Data.NHibernate
         protected override void PostProcessConfiguration(Configuration config)
         {
             // called before NewSessionFactory
-            if (!config.Properties.ContainsKey(Environment.ConnectionString))
-            {
-                throw new System.ArgumentException("Must specify connection string");
-            }
+            var settings = ConfigurationManager.ConnectionStrings[config.Properties[NHibernate.Cfg.Environment.ConnectionStringName]];
+
+	    if (settings != null)
+	    {
+	        config.Properties.Add(new KeyValuePair<string, string>(NHibernate.Cfg.Environment.ConnectionString, settings.ConnectionString));
+	    }
+
+	    // called before NewSessionFactory
+	    if (!config.Properties.ContainsKey(NHibernate.Cfg.Environment.ConnectionString))
+	    {
+		throw new System.ArgumentException("Must specify connection string. If connection_string_name is set to a value, make sure there exists a connection string with that name.");
+	    }
         }
 
     }
 
-}
\ No newline at end of file
+}