Your post is two weeks old. If you are still interested I will tell you how. I have an imported Milestone with Italian firmware running on Optus.
I did a "service upgrade" to retain all my apps and settings. That was a big mistake. The phone rebooted every night and once or twice a day. Everything was slow and jerky. Swype stopped functioning. The battery would run down in a few hours. I was ready to take a hammer to it.
Then I bit the bullet and did a factory reset to 2.2. I synced all my contacts to Gmail first, and made sure i had all the Optus settings ready. After wiping the phone clean everything was much better. Everything is now fast and smooth, Optus reconfigured automatically (after I rebooted after initial start). Battery will go all day and half way through the next. It has had only one spontaneous reboot and that was when it was in my pocket with the keyboard accidently extended. The only thing wrong is the WiFi refuses to connect to my router. It is not something i use a lot as my 3G is fine for everything i do on a phone, but i will keep working on that issue.
cheers
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