REST POST to website with provided SSL certificate (Xamarin Android) -- 2

As per the title, I need to perform a POST request to a service with a certificate that was provided by the server. More information on the current status is in this thread: [login to view URL] Basically, I'm able to perform the POST in C#, but not in Xamarin Android (I tried with HttpWebRequest, RestSharp and HttpClient). I'm requesting a simple function or class, on an empty Xamarin Android project, that is able to perform the POST request and get the data from the server. I would be providing the certificate and password, along with an explanation of the data that should be retrieved. I attach an example of the current MainActivity of the project I'm using for testing.