[c-nsp] Cisco authentication login page

[Carlo]

Hi all,
I'm trying to customize the default login page that the Cisco router 
uses for authentication proxy ( to  autenticate users ).
Can someone tell me how to do that ? I've tried to search in the Cisco 
web site, but it seems that there is no documentation about it.
Looking at the default page, i see this strange string:
<FORM ACTION="/" method="POST" target="pxywindow1"><INPUT TYPE="hidden" 
NAME="au_pxytimetag" VALUE="13502936">
I think that the au_pxytimetag value shound be different for every 
message, but i don't know how to do that.

Thanks in advance

Carlo