BIRT - Add custom authentication header to SOAP Webservice

Question

I'm using BIRT 4.3.1 and my datasource is a Webservice. Authentication is done by Josso and JOSSOID is available at my report.

I've tried to call this Webservice by SoapUi adding JOSSOID in the header. But I need to know how to do it by BIRT. I use a BIRTEclipse to edit/view the report itself.

I've searched something about WSSE but this protocol needs the username and password and I have just JOSSOID.

How could I add a custom header to this HTTP Request?