Soap AddOrder XML: response 400 Bad request.

Hi, I Have this:

<?xml version="1.0" encoding="utf-8"?>

<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

  <soap:Body>

    <AddOrder xmlns="http://tempuri.org/wsSalesQuotation/Service1">

      <SessionID>72ED6AF7</SessionID>

      <sXmlOrderObject>

       <BOM xmlns="http://www.sap.com/SBO/DIS">

        <BO>       

        <Documents>

          <row>

            <DocType>I</DocType>

            <DocDate>20130212</DocDate>

            <CardCode>C02827</CardCode>

          </row>

        </Documents>

       <Document_Lines>

</Document_Lines>

       </BO>

      </BOM>

     </sXmlOrderObject>

    </AddOrder>

  </soap:Body>

</soap:Envelope>

But when I put it into POST request I receive:

Response:  400 Bad Request

headers:  Cache-Control: private

Server: Microsoft-IIS/7.5

X-AspNet-Version: 2.0.50727

X-Powered-By: ASP.NET

Date: Tue, 12 Feb 2013 10:12:57 GMT

Connection: close

Content-Length: 0

I think that errot is located in XML between <sXmlOrderObject>.

I'm using SOAP to access this service, and Login works fine, but AddOrder doesn't work.

What do you think?, what is the minimum data for process an simply Order? Where is the problem.

Thanks in advance.