Filter API in RESTful Web Services SDK

Hi,

I am looking to filter the data in the report to export out to a file, but I could not be able to achieve this.  I am using this RESTful API:

http://<serverName>:6405/biprws/raylight/v1/documents/{documentId}/reports/{reportId}/specification - this is to apply the filter and use the following API to export to a file.

http://<serverName>:6405/biprws/raylight/v1/documents/{documentId}

The document has no data.  I use a sample similar to the one found on page 194 of the sbo41sp2_web_restful_ws_en.pdf.  Please help as I am really stuck.