Business Connector - XML to SAP using BC

Hi,

This is regarding business connector(BC).

The IDOC details are successfully converted to xml file to send third party system using BC..

But also I need the process for vice-versa ..

The data will be coming as xml data from third party system and these data need to be updated into the corresponding SAP fields.

Can you plz tell me whether any RFC's or other methods to be used?