asterisk users - Mar 2008 - How configure Voice mail for multi users.

Hi All,
 i want to configure voice mail on Asterisk 1.4 for multiple users. let
 me explain you the scenario.

 i have 10 users with the name of
 1000,2000,3000,4000,5000,6000,.......and these user can call to each
 other. Now i want to configure separate voice mail box for separate
 user.

 my extensions.conf ..... settings below..
 [voicemail]
 exten => _X.,1,Dial(SIP/${EXTEN})
 exten => _X.,n,NoOp(Dial Status: ${DIALSTATUS})
 exten => _X.,n,Goto(s-${DIALSTATUS},1)

 exten => s-NOANSWER,1,Background(vm-nobodyavail)
 exten => s-NOANSWER,n,VoiceMail(${EXTEN}@usersmail)
 exten => s-NOANSWER,n,Hangup()

 exten => s-CONGESTION,1,Background(vm-nobodyavail)
 exten => s-CONGESTION,n,VoiceMail(${EXTEN}@usersmail)
 exten => s-CONGESTION,n,Hangup()

 exten => s-CANCEL,1,Background(vm-nobodyavail)
 exten => s-CANCEL,n,VoiceMail(${EXTEN}@usersmail)
 exten => s-CANCEL,n,Hangup()

 exten => s-BUSY,1,Background(salesrep)
 exten => s-BUSY,n,VoiceMail(${EXTEN}@usersmail)
 exten => s-BUSY,n,Hangup()

 exten => s-CHANUNAVAIL,1,Background(vm-nobodyavail)
 exten => s-CHANUNAVAIL,n,VoiceMail(${EXTEN}@usersmail)
 exten => s-CHANUNAVAIL,n,Hangup()

 my voicemail.conf
 [usersmail]
 1000 => 1212, userm, 1000 at abc.com
 2000 => 1212, userm, 2000 at abc.com

 please help me how can i set calling number before send voice mail in
 users voicemail box.
 when i dial like VoiceMail(${EXTEN}@usersmail) voice mail not work and
 when i heard code user, like this VoiceMail(1000 at usersmail) voicemail
 work fine. but i want to set if user dial 2000 or 3000 or 4000 it
 should be set automatically.

 thanks for your cooperations.

 regards,
 Asif