Help needed how to pass PDF file as an attachment in webservice(SOAP)

Hi All,

Could you please throw some light on the below scenario.

It is Outbound scenario. SAP PI picks the PDF  file from  ECC  which is at Al11 locations and it has to send it to thirdparty using SOAP call.

It is passthru interface,no mapping is required.But how can we send PDF as an attachment  to thirdparty using  webservice call.

                (PDF File) Al11               (SOAP)

SAP ECC         ->                 PI            ->        Thirdpary