VIRTUAL REST service request structure


We have native restful service exposed which accepts and returns XML content, A Virtual API is created out of it and published to Mediator. I need some clarification
on the structure of the request which the Mediator application sends to the native service when invoked via Mediator.
Will the payload have the following tags appended to the request

‘<?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv=“”></soapenv:Body></soapenv:Envelope>’.

If the application appends these tags, is it possible to remove these before sending the request to Native Service ??

The following are the details

CentraSite : 9.9 (Virtual REST API created using CentraSite)
webMethods Mediator: 9.9
REST Service Source: C# application
REST Service Content-Type : application/xml
REST Client used to access the service