Cant send request to Mantis

Question

I send request to mantisBT on url my_domain/api/soap/mantisconnect.php

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="wsdl-viewer.xsl" ?>

<definitions targetNamespace="http://futureware.biz/mantisconnect" xmlns="http://schemas.xmlsoap.org/wsdl/">

  <message name="mc_loginRequest">
    <part name="username" type="xsd:string">admin</part>
    <part name="password" type="xsd:string">password</part>
  </message>

</definitions>

And response:

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
    <SOAP-ENV:Body>
        <SOAP-ENV:Fault>
            <faultcode>SOAP-ENV:Client</faultcode>
            <faultstring>Bad Request</faultstring>
        </SOAP-ENV:Fault>
    </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

I dont know what i do wrong