string strPasswordCertificate = "123456";
string strCertificate = "C:/Test/AUTH_RSA_db79bb07b4722c042e025979b3b11995fc46765b.p12";
X509Certificate x509_CertAUTH = new X509Certificate(strCertificateFilePathAUTH, strPasswordCertificate);
string strCertAUTH = x509_CertAUTH.ToString();

CreateSessionRequest CreateReq = new CreateSessionRequest();

CreateReq.x509Certificate = strCertAUTH;
string strIIN = "753159846249";

CreateReq.tin = strIIN;
WS.createSession(CreateReq);

string strPasswordCertificate = "123456";
string strCertificate = "C:/Test/AUTH_RSA_db79bb07b4722c042e025979b3b11995fc46765b.p12";
X509Certificate x509_CertAUTH = new X509Certificate(strCertificateFilePathAUTH, strPasswordCertificate);
string strCertAUTH = x509_CertAUTH.ToString();

CreateSessionRequest CreateReq = new CreateSessionRequest();

CreateReq.x509Certificate = strCertAUTH;
string strIIN = "753159846249";
CreateReq.tin = strIIN;

string _userName = 123456789011
string _UserPassword = "TestPass123"

UsernameToken userToken;

userToken = new UsernameToken(_userName, _UserPassword, PasswordOption.SendPlainText);

SessionService WS = new SessionService();
SoapContext requestContext = WS.RequestSoapContext;
requestContext.Security.Tokens.Add(userToken);

WS.createSession(CreateReq);