SugarMEmE, just a thought, since u need to copy it manually, u need standalone iOS5.1.1sdk. I checked Xcodes4.2.x up to Xcode4.5, they do not have iOS5.1.1, just 5.1 and then 6.0. No intermediates. So if somebody has a Lion w Xcode4.2 or higher, that can download those intermediates automatically, you technically just could copy it from there.
Hei, just did it. You need to find a file iPad1,1_5.1.1_9B206_restore.ipsw say here: http://mytopfiles.com/other/file/iPad1,1_5-1-1_9B206_Restore/589434.htm
It was on my other Mac (that has Lion and Xcode 4.3) in Library\iTunes\iPad Software Updates\
I just copied it on my Mac (Snow Leopard w Xcode4.2) in the same Library\iTunes\iPad Software Updates.
Image immediately showed up in Xcode Organizer Library Software Images.
And right away I was able to build on my iPad1 with iOS5.1.1
Logically, if you need it for iPad2 you would look for iPad2,1_5.1.1_9B206_restore.ipsw http://mytopfiles.com/other/file/iPad2,1_5-1-1_9B206_Restore/589852.htm etc, I guess.
Regards,
B
PS after all, u do not need to pay for upgrade to Lion yet.