Hi,
1. Model a Outbound Service in PI
2. Generate Proxy.
3. Configure Integration Service (PI System) in SAP Backed System
4. You test outbound service from SPROXY .
http://wiki.sdn.sap.com/wiki/display/profile/ABAP+Proxy+outbound+program+-+purchase+order+send
Thank You
Regards
Goverdhan Totawar