Hi,
You may follow the link ABAP Proxy (Complete Developments on SAP-PI & SAP-ABAP Systems)
http://wiki.scn.sap.com/wiki/display/XI/Step-by-step+FTP+to+ABAP+Proxy
You need to write the code inside the Provider Class ->Method.
Create an internal table to capture the data from the proxy structure and append that to the table you have created.
Suman