Assigning Task in Outlook 2003 POP3 Setup

Hi everyone. This is James Clark, I just want to ask about my problem in Assigning task in outlook 2003. Our current setting is POP3 Setup. I dont know if Assigning Task is applicable to our current setup.

Details:
1. i want to assign task to someone. and i did create New Task then click the assign task button, enter on recipient field and others. then click send.
2. the recipient received the message, but it is just a usaul message, not a assigned task that the recipient will accept or decline the task request.