rc.cs

public void Merge()
{
    // create a Dictionary with all form values
    Dictionary<string,string> formValues = 
      new Dictionary<string,string>();

    foreach (string key in Request.Form)
    {
        formValues.Add(key, Request[key]);
    }

    // create a new ReportingCloud object
    ReportingCloud rc = new ReportingCloud("username", "password");

    // create a MergeBody object with the form values
    MergeBody mb = new MergeBody()
    {
        MergeData = formValues
    };

    // call the MergeDocument method
    List<byte[]> documents = rc.MergeDocument(mb, "letter.tx");

    // return the PDF to the browser
    Response.ContentType = "application/pdf";
    Response.BinaryWrite(documents[0]);
    Response.Flush();
    Response.End();
}