Copy source XML up on successful completion of Proxy in ECC

Hello,

I have a interface SOAP-->PI-->Proxy, SOAP xml will contain multiple records in it. Up on successful execution of all the records from xml file in ECC proxy, i have to write/copy the same source soap xml to FTP folder.

Here basically source xml(provided xsd) is too big and so many unwanted tags in it. So proxy structure we are maintaining with only required fields.

So Is there any way that we can copy/replicate same xml sent from source web service call to FTP server up on successful execution of proxy ?

Regards