Go to Start, Settings, Connections tab
Tap the Connections applet
Tap the Advanced tab
Tap the Select Networks button
Under "Programs that automatically connect to the Internet should connect using:", tap New
Enter "My ISP name" as "Optus MMS Settings"
Tap the "Modem" tab
Tap the "New" button
Under "Make New Connection", enter the connection name as "Optus MMS"
Change the Modem from "Cellular Line" to "Cellular Line (GPRS)" and click Next
Enter the access point name as "mms" and click Next
Tap Finish
Change the "Programs that automatically connect to the Internet should connect using:" back to your original Internet connection
Tap OK

Launch Message software
Go to the Tools, Options menu
Unclick "Download on home network only"
Tap on the Servers tab
Enter the "Server Name" as "Optus"
Enter the "Gateway" as "61.88.190.10"
port = 9201
Enter the "Server Address" as http://mmsc.optus.com.au:8002/

Set Optus as default server