[Help-gnu-radius] How to use rewrite function

[sy sy]

I define a test function in raddb/rewrite file as following:
 integer  test()
{
  %[User-Name] = %[User-Name]+".ppp";
   %[NAS-Port-Id] = 1;
   return 0;
}
In file raddb/huntgroups I define as following:
DEFAULT NAS-IP-Addres = 192.168.0.1
               Rewrite-Function = "test"
So requestes from NAS 192.168.0.1 will be rewrited ,attribute User-Name will be 
changed and attribute NAS-Port-Id which is not presented in request will be set 
to 1 .
But it is not work,Why ?

                
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