How make soap request using C#

Question

Hello,

I am tried do query to web service. To content I am put next one:

strSoapEnvelope = "<?xml version=\"1.0\"?>";
strSoapEnvelope += "<soap:Envelope ";
strSoapEnvelope += "xmlns:xsi = \"http://schemas.xmlsoap.org/wsdl/\" ";
strSoapEnvelope += "xmlns:xsd= \"http://www.w3.org/2001/XMLSchema\" ";
strSoapEnvelope += "xmlns:soap= \"http://schemas.xmlsoap.org/wsdl/soap/\">";
strSoapEnvelope += "<soap:Body>";
strSoapEnvelope += "<Method xmlns=\"http://schemas.xmlsoap.org/wsdl/\">";
strSoapEnvelope += "<Str1>string_1</Str1>";
strSoapEnvelope += "<Str2>string_2</Str2>";
strSoapEnvelope += "<Str3></Str3>";
strSoapEnvelope += "<complexType name=\"SomeStruct\">";
strSoapEnvelope += "<sequence>";
strSoapEnvelope += "<element name=\"Param1\"></element>";
strSoapEnvelope += "<element name=\"Param2\"></element>";
strSoapEnvelope += "<element name=\"Param3\"></element>";
strSoapEnvelope += "<element name=\"Param4\"></element>";
strSoapEnvelope += "<element name=\"Param5\"></element>";
strSoapEnvelope += "</sequence>";
strSoapEnvelope += "</complexType>";
strSoapEnvelope += "</Method>";
strSoapEnvelope += "</soap:Body>";
strSoapEnvelope += "</soap:Envelope>";

And response is:

<?xml version="1.0"?><SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body><SOAP-ENV:Fault><faultactor/><faultcode>SOAP-ENV:Server</faultcode><faultstring>Invalid SOAP request</faultstring></SOAP-ENV:Fault></SOAP-ENV:Body></SOAP-ENV:Envelope>


First I tried do Web reference, I got all functions and parameters to use. When I made this method I got error: Cannot convert System.bool to System.String.
This function return boolean value, string value and someStruct struct.