Heck, even if I take the POST data out of HTTPWatch (which works) and stick it on a url in IE and submit it as a GET, i get the html fragment for the login page:

Code:
https://www.vyke.com/index.jsf?AJAXREQUEST=_viewRoot&topMenuForm=topMenuForm&autoScroll=&javax.faces.ViewState=j_id56452&topMenuForm%3AopenLoginForm=topMenuForm%3AopenLoginForm&
But appending the login post data just realises the same "empty" response