MUX patch

QMUX patch

diff --git a/jpos/src/main/java/org/jpos/q2/iso/QMUX.java b/jpos/src/main/java/org/jpos/q2/iso/QMUX.java
index cedffdc..1dacefa 100644
--- a/jpos/src/main/java/org/jpos/q2/iso/QMUX.java
+++ b/jpos/src/main/java/org/jpos/q2/iso/QMUX.java
@@ -271,6 +271,8 @@ public class QMUX
             if (timeout > 0)
                 DefaultTimer.getTimer().schedule (ar, timeout);
         }
+        if (sp.rdp (req))
+            throw new ISOException ("Duplicate key " + req + " detected");
         sp.out (req, ar, timeout);
         sp.out (out, m, timeout);
     }