AT&T unlock of my iPhone 3g not working

After haggling for some time with AT&T, i received an email saying:

We have reviewed your request and confirmed that you are eligible to have the requested iPhone unlocked.

To complete the unlock, simply:
1. Open iTunes on your Mac or PC and verify that you have internet connectivity.
2. Connect your iPhone using the dock connector to USB cable that came with your iPhone.

3. Backup and restore your iPhone using iTunes .
For information on backup and restore, please visit http://support.apple.com/kb/HT1414.

4. After restoring, your iPhone will be unlocked.

Additional information on unlocking can be found at http://support.apple.com/kb/TS3198.

The latter article says: "

If your carrier has unlocked your iPhone, after connecting your iPhone to iTunes, you should see this message: "Unlock Complete. Congratulations, your iPhone has been unlocked. To set up and sync this iPhone, click Continue."

However, connecting my old jailbroke 3G and hitting the restore button did not result in an "unlock complete" message as indicated, but only error message 1015 and a bricked phone (stuck in recovery mode). I used other methods to get it back to life, but it is not properly unlocked, and is stuck on OS 4.1. If i click on the "update" button, it goes to error 1015 again, stuck in recovery mode.

Is there no way to bring my phone back into normal mode, really unlocked and restored to a normal apple state? It works now (using T-mobile here in europe), but i would like to update it, and sync it as it should be.