Try to add this into the <Install Path>Package Server\ps\web.config:
<add key="ServePageEnabled" value="True"></add>
(yes funny spelling)
Then access this url:
http://<server_address>:<port>/ps/ps.svc/package/server/id?ClientID=%UDID%
replace <server_Address> and <port> with actual values for your environment..
Br
Peter