Index: core/nhttp/src/main/java/org/apache/synapse/transport/nhttp/Axis2HttpRequest.java
===================================================================
--- core/nhttp/src/main/java/org/apache/synapse/transport/nhttp/Axis2HttpRequest.java	(revision 130186)
+++ core/nhttp/src/main/java/org/apache/synapse/transport/nhttp/Axis2HttpRequest.java	(working copy)
@@ -237,7 +237,12 @@
                 if (header instanceof String && value != null && value instanceof String) {
                     if (!HTTPConstants.HEADER_HOST.equalsIgnoreCase((String) header)) {
                         httpRequest.setHeader((String) header, (String) value);
+                    } else {
+                        if(msgContext.getProperty("REQUEST_HOST_HEADER") != null) {
+                            httpRequest.setHeader((String) header, (String)msgContext.getProperty("REQUEST_HOST_HEADER"));
+                        }
                     }
+
                 }
             }
         }