thx for your help, now everthing is working perfect.
I recorded my own .gsm for the menu, here is the code i use now, maybe its helpful:
; the shutdown services on my server
exten => 99,1,SetLanguage(de)
exten => 99,2,Answer
exten => 99,3,DigitTimeout,5
exten => 99,4,ResponseTimeout,10
exten => 99,5,Wait(1)
exten => 99,6,Authenticate(${ADMINPW})
exten => 99,7,Goto(Administration,s,1)
[Administration]
exten => s,1,SetLanguage(de)
exten => s,2,DigitTimeout,5
exten => s,3,ResponseTimeout,10
exten => s,4,BackGround(admin-greetings)
exten => 1,1,BackGround(admin-restarting-ppp)
exten => 1,2,System(sudo /usr/bin/killall ppp)
exten => 1,3,Wait(2)
exten => 1,4,System(sudo /usr/bin/killall -9 ppp)
exten => 1,5,Wait(2)
exten => 1,6,System(sudo /etc/rc.d/ppp-user start)
exten => 1,7,Playback(admin-ppp-restart)
exten => 1,8,Goto(s,1)
exten => 2,1,System(sudo /sbin/reboot)
exten => 2,2,Playback(admin-reboot)
exten => 2,3,Hangup