In order to change this banner please follow this procedure :
1.Use an editing tool to edit the following file:
Lm\POP3SVC\virtual server number
2. Click Edit, click New, and then click String Record
3. Verify that the entry in the ID box is Other, and then type the decimal string 41661 at the side of the id box.
4. At the Data box, type the banner that you want to be display ( when using Server 2003 and the IIS 6.0 version of Metaedit, double click the new value you added and enter the text for displaying)
5. restart POP3 service.
6. you can telnet to port 110 of the virtual server to see if The original banner exist.