The WSRP Consumer and the WSRP Producer in the portal support two-phase rendering for JSR 286 portlets. This allows a remote portlet to set headers and cookies and to modify the HTML head section. The WSRP Producer determines whether a JSR 286 portlet requires two-phase rendering and, if it does, the Producer invokes the render method in two phases.
The Producer does not pass any headers that are contained in this list to the Consumer, and the Consumer does not pass any headers that are contained in this list to the Producer.
You can set this parameter in the portal WP Configuration Service by using the WebSphere® Integrated Solutions Console.