Well i belive i found a workaround solution for this issue.
I just use the WebBrowser instead of the WebClient and have the WebBrowser render the hole site before extracting the HtmlDocument. takes time, but it works.
heres the code
public HtmlDocument GetHtmlAjax(Uri uri, int AjaxTimeLoadTimeOut)
{
using (WebBrowser wb = new WebBrowser())
{
wb.Navigate(uri);
while (wb.ReadyState != WebBrowserReadyState.Complete)
Application.DoEvents();
Thread.Sleep(AjaxTimeLoadTimeOut);
Application.DoEvents();
return wb.Document;
}
}