Sending XML as a string to a wsdl on Integration Server

Hi All,
I have a wsdl provider on Integration Server where in the input there is only 1 string field. If I send XML in that string, in IS it gets converted to a XML document with the same name as the field. is that normal behaviour? if yes then is there any way to avoid it. I would like to received the same XML string which was sent to the wsdl URL.