--- a/mercurial-server/src/jetbrains/buildServer/buildTriggers/vcs/mercurial/MercurialVcsSupport.java	Fri Sep 27 18:03:57 2013 +0200
+++ b/mercurial-server/src/jetbrains/buildServer/buildTriggers/vcs/mercurial/MercurialVcsSupport.java	Mon Sep 30 13:04:11 2013 +0200
@@ -21,7 +21,10 @@
 import jetbrains.buildServer.buildTriggers.vcs.mercurial.command.exception.AbandonedTransactionFound;
 import jetbrains.buildServer.buildTriggers.vcs.mercurial.command.exception.UnrelatedRepositoryException;
 import jetbrains.buildServer.log.Loggers;
-import jetbrains.buildServer.serverSide.*;
+import jetbrains.buildServer.serverSide.InvalidProperty;
+import jetbrains.buildServer.serverSide.PropertiesProcessor;
+import jetbrains.buildServer.serverSide.ServerListener;
+import jetbrains.buildServer.serverSide.ServerListenerAdapter;
 import jetbrains.buildServer.util.EventDispatcher;
 import jetbrains.buildServer.util.FileUtil;
 import jetbrains.buildServer.util.cache.ResetCacheRegister;
@@ -37,7 +40,6 @@
 import java.net.URISyntaxException;
 import java.util.*;
 
-import static java.util.Collections.emptyMap;
 import static jetbrains.buildServer.buildTriggers.vcs.mercurial.HgFileUtil.deleteDir;
 
 /**
@@ -662,6 +664,6 @@
       if (extensionClass.isInstance(e))
         return extensionClass.cast(e);
     }
-    return null;
+    return super.getVcsCustomExtension(extensionClass);
   }
 }