iphone OS lower than 4 ==> Testing iAd?

I implemented iad to my app (sdk 4), i set the target to be able to run OS 3 and higher now i need to test and make sure that devices with OS 4 lower won'开发者_如何学运维t crash because of iAd. Is there a way to go back to iphone OS 3.2 to test this. Where can i download it, apple has removed it from their website.

when you install sdk 4, sdk 3.2 should still be there as that is the separate iPad OS, in the top left corner of the code editor just select the dropdown and choose 3.2 (device or simulator)