How to communicate with service over http post
<p>I have a back-end service layer that needs to communicate with an external service that is accessible through an <code>HTTP POST</code>. </p>

<p>The external service does not contain a WSDL definition and is not a REST API.</p>

<p>The following HTML code successfully communicates with the external http service:</p>

<pre><code>&lt;html&gt;
&lt;body&gt;
    &lt;form enctype="multipart/form-data" action="http://externaladress/fileService/upload" 
          method="post"&gt;
        &lt;input type="hidden" name="username" value="username" /&gt;
        &lt;input type="hidden" name="password" value="password" /&gt;
        &lt;input type="hidden" name="destinationId" value="10" /&gt;

        Choose a file to upload: &lt;input name="uploadfile" type="file" /&gt;&lt;br /&gt;
        &lt;input type="submit" value="Upload File" /&gt;
    &lt;/form&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>The problem is I am not in the context of a web page, but in the context of a web-service that is running on the back end looking to call said external service. </p>

<p>How can I accomplish this?</p>