Post an XML document to the web service at the URL

PostToWebservice.cs

public byte[] Register(string url, string emailAddress, string firstName, string lastName)
{
	var swr = new StringWriter();
	var xws = new XmlWriterSettings {OmitXmlDeclaration = true};

	using (XmlWriter xwr = XmlWriter.Create(swr, xws))
	{
		xwr.WriteStartElement("register");
		xwr.WriteAttributeString("email", emailAddress);
		xwr.WriteAttributeString("firstname", firstName);
		xwr.WriteAttributeString("lastname", lastName);
		xwr.WriteEndElement();
	}

	byte[] arrRequestBytes = Encoding.UTF8.GetBytes(swr.ToString());

	return _wclMain.UploadData(url, "POST", arrRequestBytes);
}