Web Services - How to add namespace to parameter?

Hello,

I`m facing problem with "certification verification failed" during sending signed message via web service.

In my opinion it is because element/parameter SIGNATURE in xml is like:

<n2:Signature Id="Signature-0">

and should be:

<n2:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#" Id="Signature-0">

Originally proxy structure was very complexed element "Signature" so every part we had to put separately.

Now i tried to modify wsdl and set "Signature" as string so we can send only one parameter with correct xml to function module and next to web service.

Now we are able to add everything inside "Signature" but still first element is generated by SAP

Modified WSDL part is like:

      <xs:element name="UploadRequest">

        <xs:complexType>

          <xs:sequence>

                              <xs:element minOccurs="0" name="Signature" type="xs:string"/>

          </xs:sequence>

        </xs:complexType>

      </xs:element>

so in SAP under request parameter we have only Signature type string.

My question is:

Is it possible to add namespace xmlns:ds="http://www.w3.org/2000/09/xmldsig#" to "Signature"?

If so how can I do this?

Best regards