public static RestRequest BuildContactRequest(this PostalAddress postalAddress, string href)
{
var contactRequest = new RestRequest(href, Method.POST);
contactRequest.AddHeader("Content-Type", "application/x-www-form-urlencoded");
var queryParameters = HttpUtility.ParseQueryString(HttpUtility.UrlDecode(href));
var mobjnr = queryParameters["tx_sozaltbau_pi1[mobjnr]"];
var mlfd = queryParameters["tx_sozaltbau_pi1[mlfd]"];
contactRequest.AddQueryParameter("xajax", "processMailForm");
contactRequest.AddQueryParameter("xajaxargs[]", postalAddress.BuildAjaxQuery());
contactRequest.AddQueryParameter("xajaxargs[]", mobjnr);
contactRequest.AddQueryParameter("xajaxargs[]", mlfd);
return(contactRequest);
}