Update: Rebex HTTPS for .NET has been officially released in February 2017.
http://blog.rebex.net/https-with-tls-12-sha2-sni/
Yes, this is possible.
ASMX/WSDL generates stub objects that are inherited from System.Web.Services.Protocols.SoapHttpClientProtocol, which provides a protected virtual WebRequest GetWebRequest(Uri uri) method. The default implementation of that method calls System.Net.WebRequest.Create to get an instance of WebRequest, which means that registering our HttpRequestCreator class with WebRequest class as a handler for HTTP and HTTPS schemes causes the generated web service stub objects use the Rebex.Web client:
var creator = new HttpRequestCreator();
// enable TLS 1.0, 1.1 and 1.2 (and disable legacy SSL 3.0)
creator.Settings.SslAllowedVersions = TlsVersion.TLS10 | TlsVersion.TLS11 | TlsVersion.TLS12;
// register HTTP request creator to replace .NET CF's default HttpWebRequest
creator.Register();
Alternatively, you might override the stub's GetWebRequest method to create an instance of Rebex.Web client instead of the default one:
protected override WebRequest GetWebRequest(Uri uri)
{
var creator = new HttpRequestCreator();
// enable TLS 1.0, 1.1 and 1.2 (and disable legacy SSL 3.0)
creator.Settings.SslAllowedVersions = TlsVersion.TLS10 | TlsVersion.TLS11 | TlsVersion.TLS12;
return ((IWebRequestCreate)creator).Create(uri);
}
By the way, we are going to release a new version of Rebex.Web client on Rebex Labs soon - if you would like to get informed when it's ready, please subscribe to Rebex Labs newsletter.