Create SAML response from assertion in C # 4.5 (WIF)

I need a way to send a message <samlp:response>

to a specific url, its pretty simple and .NET helps me with the class Saml2Assertion

, but I can't find a way to wrap this assertion in a response and serialize (or even send without a manual message)?

Saml2Assertion assert = new Saml2Assertion(new Saml2NameIdentifier("SAMLIssuer"));
assert.Subject = new Saml2Subject(new Saml2NameIdentifier("10001", new Uri("urn:oasis:names:tc:SAML:2.0:nameid-format:persistent")));
Saml2AuthenticationContext context = new Saml2AuthenticationContext(new Uri("urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport"));
assert.Statements.Add(new Saml2AuthenticationStatement(context, DateTime.Now));

string assertion;
using (var sw = new StringWriter())
{
    var xws = new XmlWriterSettings();
    using (var xw = XmlWriter.Create(sw, xws))
    {
        var handler = new Saml2SecurityTokenHandler();
        handler.WriteToken(xw, new Saml2SecurityToken(assert));
    }
    assertion = sw.ToString();
}

      

        
        
        
      

    

And the XML I get for assert seems to be fine:

<?xml version="1.0" encoding="utf-16"?>
<Assertion ID="_fc348927-c0bf-4955-b98f-483043d8dedd" IssueInstant="2017-04-19T11:29:38.464Z" Version="2.0" xmlns="urn:oasis:names:tc:SAML:2.0:assertion">
    <Issuer>SAMLIssuer</Issuer>
    <Subject>
        <NameID Format="urn:oasis:names:tc:SAML:2.0:nameid-format:persistent">10001</NameID>
    </Subject>
    <AuthnStatement AuthnInstant="2017-04-19T11:29:39.040Z">
        <AuthnContext>
           <AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport</AuthnContextClassRef>
        </AuthnContext>
    </AuthnStatement>
</Assertion>

      

        
        
        
      

    

So what now? How to get the code from my code:

<samlp:Response
    xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
    xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
    ID="new id"
    InResponseTo="old id"
    Version="2.0"
    IssueInstant="2017-04-19T11:29:39.040Z"
    Destination="some url">
    <saml:Issuer>SAMLIssuer</saml:Issuer>
    <samlp:Status>
      <samlp:StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/>
    </samlp:Status>
    <saml:Assertion ....

      

        
        
        
      

    

without using external libraries or creating your own wrappers / string connections? I can't find anything in the .NET 4.5 WIF implementation that can help me.