Problem with ErpObjectDFFUpdateService SOAP

Content

Hi, 

I'm trying use the service with SOAP and i have some questions of how to use this Service. 

I always got the '0' returns.

This is my Payload:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/&quot; xmlns:typ="http://xmlns.oracle.com/apps/financials/commonModules/shared/model/erpIntegrationService/types/&quot; xmlns:erp="http://xmlns.oracle.com/apps/financials/commonModules/shared/model/erpIntegrationService/"&gt;
   <soapenv:Header/>
   <soapenv:Body>
      <typ:updateDffEntityDetails>
         <!--Optional:-->
         <typ:document>
            <erp:Content>NULL</erp:Content>
            <erp:FileName>#NULL</erp:FileName>
            <!--Optional:-->
            <erp:ContentType>#NULL</erp:ContentType>
            <!--Optional:-->
            <erp:DocumentTitle>#NULL</erp:DocumentTitle>