Exemplo de chamada
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:systax_erp_cenario">
<soapenv:Header/>
<soapenv:Body>
<urn:systax_erp_cenario>
<username> usuário</username>
<senha>senha</senha>
</urn:systax_erp_cenario>
</soapenv:Body>
</soapenv:Envelope>