I need to sign a XML document.
<soapenv:Header/>
<soapenv:Body>
<smk:operationCode>
<oper:operationCodeRequest>
<typ:Id>?</typ:Id>
<typ:Date>?</typ:Date>
<typ:Code>?</typ:Code>
<oper:Val>?</oper:Val>
</oper:operationCodeRequest>
</smk:operationCode>
</soapenv:Body>
</soapenv:Envelope>
<soapenv:Envelope xmlns:oper="http://***.es/OperationStatus" xmlns:smk="http://***.es"
<ds:SignedInfo>
</ds:CanonicalizationMethod>
<ds:Reference URI="#id-194D65A85DD46269DF1..">
<ds:Transforms>
</ds:Transform>
</ds:Transforms>
<ds:DigestValue>rmJDCesz4UZvAM6auZ1S...v4=</ds:DigestValue>
</ds:Reference>
</ds:SignedInfo>
<ds:SignatureValue>wtd...uA==</ds:SignatureValue>
<ds:KeyInfo Id="KI-194D65A85DD46269DF...">
<wsse:SecurityTokenReference wsu:Id="STR-194D65A85DD46269DF...">
</wsse:SecurityTokenReference>
</ds:KeyInfo>
</ds:Signature>
</wsse:Security>
</soapenv:Header>
<smk:operationCode>
<oper:operationCodeRequest>
<typ:Id>?</typ:Id>
<typ:Date>?</typ:Date>
<typ:Code>?</typ:Code>
<oper:Val>?</oper:Val>
</oper:operationCodeRequest>
</smk:operationCode>