execute programme when receiving account packet

Hi, All i'd like to execute an external program when receiving an Accounting-Request. I've try exec ipoque { wait = yes program = "/bin/sh /opt/mytest %{User-Name}" input_pairs = request output_pairs = reply shell_escape = yes output = none packet_type = Accounting-Request } But the program is not execute even if I comment packet_type = Accounting-Request line (#packet_type = Accounting-Request). Can someone help me please. Regards.