Member State Change in Realtime Queue

Hi ,
I have done the realtime queue using odbc . it is working fine . But the problem is that , the agent member state is not working . For Example , I have put a caller in queue and one agent phone is ringing . The state of the queue member at the time of ringing .
Local/500@queue (realtime) (In use) has taken no calls yet

After that agent answered the call , the state of the queue member is
Local/500@queue (realtime) (Not in use) has taken no calls yet .

But the problem is , after answer the call , the state should be “Busy” . but the asterisk is showing me as "Not in use " . Is there any configuration which i have to do for realtime queue .

Thanks

Local channels don’t normally have valid device state values. Asterisk cannot work out how many different workstations could be accessed by the one local channel.