Unlocking iPhone without upgrading to 5.1

I recently called AT&T and was able to get them to agree to unlock my iPhone 4 as my contract has been paid of.

They unlocked it and then told me that all I need to do is to restore the phone thru iTunes and it would be unlocked.

Here is my problem. If I restore my phone thru iTunes, it will automatically upgrade my phone to 5.1.
I am currently running 5.0.1 which is jail broken.

I am told that no jailbreak is available for 5.1

The reason I am needing an unlocked, jail broken iPhone is for travel using an international sim card.

What are my options....please help

Thanks

Download iFaith (or Redsn0w) an backup your SHSH blobs then just make a signed .ipsw and then restore to that.

Ok guys, I have no clue what you are talking about.
Could you please explain the process needed in very simple terms. Step by step


Thanks

1. CLOSE ITUNES (till I tell you to open it)
2. go to iH8sn0w.com and download iFaith 1.4 for your OS
3. Extract it to a folder on the desktop of your computer called "iFaith Restore"
4. If on Windows run iFaith as an Administrator
5. Open iFaith and press ok then press "Dump SHSH Blobs"
6. Then press Proceed and Press no if you get the "Are you dumping SHSH for Apple TV 2"
7. Press Start and follow the onscreen instructions to put your device in DFU mode
8. Wait. This process will take about 5-10 mins
9. Once the SHSH have been backed up close iFaith
10. Re Open iFaith and press "Build *Signed* .ipsw /w blobs"
11. Press "Browse for SHSH blobs cache"
12. Navigate to the iFaith Restore folder on your computers desktop and press the file that should have a name something like this 00000343A914B474_iPhone_4-5.0.1_(9A405)-blobs
13. open that file and the browse and select the iOS 5.0.1 .ipsw that you have downloaded if you have not downloaded the iOS 5.0.1 .ipsw press Download it for me (if you do this the process will be alot (5-10) longer
14. Press Build ipsw
15. Wait (this procces will take about 7-10 mins)
16. Once iFaith has promped you that the .ipsw has been built close iFaith
17. Re Open iFaith for the last time and this time press Use DFU Pwner (iREB)
18. Put your device in DFU and let iFaith do its thing
19. Once you have been prompted that the process has completed close iFaith
20. Open iTunes (you will be prompted that there is a device in recovery mode just press OK) now hold SHIFT on your keyboard and press restore
21. Navigate to the iFaith Restore folder on your desktop and open the file that is names something like this 00000343A914B474_iPhone_4-5.0.1_(9A405)-SIGNED.ipsw
22. Press restore and let the iTunes restore finish

Now you can upgrade to any firmware you want and to downgrade back to iOS 5.0.1 at any time just repeat steps 17-22

-Redsn0wier