Is it possible to upgrade iOS offline?

I have an iPad 3 iOS5.1.1 jailbroken.
Now that iOS 7 (exactly 7.0.3) is on the Apple update servers, I want to know if I am able to update my iOS to 6.1.2 or not.

I downloaded the firmware of 6.1.2 and want to update to this except iOS 7.0.3.
Anytime I want to update it via iTunes, it wants to check it with Apple servers and obviously they say you should upgrade to 7.0.3.

Is there any way I can upgrade my iOS to 6.1.2?


This answer has been moved to a more generic question: https://apple.stackexchange.com/a/114076/18387