I’ve tested this and it works like a charm. It uses a custom ipcc file that has been edited with Starhub settings. By right, M1 users can also try to edit their own ipcc files. An ipcc file is essentially a zip file, just rename the ipcc to zip, open it up and edit using a text editor the carrier.plist files with M1 settings.

UPDATE: This works for the iPhone 3GS as well.

StarHub users, follow the steps below to enable MMS & Tethering!

1. Connect iPhone to iTunes and backup your iPhone just to be safe. After backup, disconnect your iPhone.

2. Follow the instructions on how to enable carrier bundle support in iTunes 8.2. For Mac Users. For Windows Users

3. After enabling carrier bundle support, proceed to download the custom ipcc file here or here.

4. Start iTunes and connect your iPhone.

5. Option + Check for Update (Mac) or Shift + Check for Update (Win) and select the ipcc file to update.

6. iTunes will update your iPhone. You can go to Settings >> General >> Network >> Cellular Data Network and see ’shwapint’ as the APN for Cellular Data and ’shmms’ as the APN for MMS. Do not change these settings as Tethering will cease to work if you do.

7. Restart your iPhone and test MMS & Tethering! It should work!