Export parameter REALLY work in message mapping???????

Question

I wrote a java version transformation and it worked good with export parameter.
However I can not work it out in graphical message mapping. I refered http://help.sap.com/saphelp_nwpi71/helpdata/en/43/c3e1fa6c31599ee10000000a1553f6/frameset.htm.
In PI7.1, I add an export parameter "EXPORT_PARA" in the "Signature" tab. Are there any special step to assign this parameter to an UDF? I did not find a way to do it.
And then I define an UDF,
    public String SetExportPara(String sss, Container container) throws StreamTransformationException{
     String str = "GOOD";
     GlobalContainer gc = container.getGlobalContainer();
     OutputParameters paras= gc.getOutputParameters();
if(paras.exists("EXPORT_PARA ") == true) {
     paras.setString("EXPORT_PARA ", str);
}else {
  str = "NOT FOUND EXPORT_PARA";
return str;
And I assign this UDF to one element of my output XML, I tried to run it in IE, it always output "NOT FOUND EXPORT_PARA.
why?????
I searched the forum, no answer found.

Answer 1

I hope you are referring to Parameterized mapping concept of SAP PI7.1
To have this in Message Mapping you dont need any UDF/ JAVA code!
Just follow this blog and you should be done: /people/jin.shin/blog/2008/02/14/sap-pi-71-mapping-enhancements-series-parameterized-message-mappings
Regards,
Abhishek