Add endpoint header security WCF programmatically

I've this web.config file to configure client proxy from a external service this service required authentication on the messages header, I've the service well configured on my web.config but for now I'm try create the proxy with this configuration on code,with propose change dynamically the user and password.

<cliente>
    <endpoint address="https://wwwww.hhhahdhadhs.askadadasda" binding="basicHttpBinding" bindingConfiguration="MyConfiguration" contract="PROXY_ACSS_SERVICES.RegistoPrescricaoMedicamentos">
            <headers>
              <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
                <wsse:UsernameToken>
                  <wsse:Username>MyUser</wsse:Username>
                开发者_运维百科  <wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">87726655434</wsse:Password>
                </wsse:UsernameToken>
              </wsse:Security>
            </headers>
          </endpoint>
</cliente>

<basicHttpBinding>
<binding name="PrescricaoMedicamentos" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true">
          <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
          <security mode="Transport">
            <transport clientCredentialType="None" proxyCredentialType="None" realm="" />
            <message clientCredentialType="Certificate" algorithmSuite="Default" />
          </security>
        </binding>
</basicHttpBinding>

My problem is create the header where defined the username and password,

<headers>


   <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
            <wsse:UsernameToken>
              <wsse:Username>MyUser</wsse:Username>
              <wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">87726655434</wsse:Password>
            </wsse:UsernameToken>
          </wsse:Security>
        </headers>  

Thanks in advance

EDIT

Ladislav Mrnka after I create the proxy programmatically receive this message

'The request channel timed out attempting to send after 00:00:59.9829990. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout.'

This is my proxy configuration

   BasicHttpBinding binding = new BasicHttpBinding(BasicHttpSecurityMode.TransportWithMessageCredential);
            binding.Name = "PrescricaoMedicamentos";
            binding.CloseTimeout = new TimeSpan(0, 1, 0);
            binding.OpenTimeout = new TimeSpan(0, 1, 0);
            binding.ReceiveTimeout = new TimeSpan(0, 10, 0);
            binding.SendTimeout = new TimeSpan(0, 1, 0);
            binding.AllowCookies = false;
            binding.BypassProxyOnLocal = false;
            binding.HostNameComparisonMode = HostNameComparisonMode.StrongWildcard;
            binding.MaxBufferSize = 65536;
            binding.MaxBufferPoolSize = 524288;
            binding.MaxReceivedMessageSize = 65536;
            binding.MessageEncoding = WSMessageEncoding.Text;
            binding.TextEncoding = System.Text.Encoding.UTF8;
            binding.TransferMode = TransferMode.Buffered;
            binding.UseDefaultWebProxy = true;
            binding.ReaderQuotas = new XmlDictionaryReaderQuotas()
                                       {
                                           MaxDepth = 32,
                                           MaxStringContentLength = 8192,
                                           MaxArrayLength = 16384,
                                           MaxBytesPerRead = 4096,
                                           MaxNameTableCharCount = 16384
                                       };

            binding.Security.Message.ClientCredentialType = BasicHttpMessageCredentialType.UserName; 


            return binding;

}

I wondering if is possible add a static header to all messages in code.. Something like AddressHeader.CreateAddressHeader( 'authentication header') and apply this headers on my EndpointAddress configuration. This kind of approach substitute literal my first code

<headers>
          <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
            <wsse:UsernameToken>
              <wsse:Username>myusername</wsse:Username>
              <wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">mypass</wsse:Password>
            </wsse:UsernameToken>
          </wsse:Security>
        </headers>

If the service correctly implements user name token profile change the security settings in your binding to:

<security mode="TransportWithMessageCredential">
    <message clientCredentialType="UserName" />
</security>

And once you create a proxy set credentials by:

proxy.ClientCredentials.UserName.UserName = ...;
proxy.ClientCredentials.UserName.Password = ...;