cisco 7940 7960 HTTP Erro[12]!

I'm devoloping XML Services for cisco Ip Phones..
my page has a refresh paramter at top without url setted..
i tried 7941,9971,9741 e.g phone types
pages are rendered without any error...
but for 7960 7940
first page is rendered but when refresh is come..it writes Host Not Found
after HTTP Error [12]!

this was because..this kind of phone web browser is not smarter enough to handle refresh parameter without url defined so i changed

HttpContext.Current.Response.AddHeader("refresh","30");


HttpContext.Current.Response.AppendHeader("refresh", "30;URL=http://....")

this worked thanks to
this content