I use my custom buttons for UIActionSheet. It works good for iOS 5 and iOS 6 but in the iOS 7 I have problems. The buttons overdraw each other.
As per Apple's iOS 7 UI Transition Guide, some related constants, such as UIActionSheetStyle are not supported in iOS 7.
Apple wants to control the temporary modal views more in iOS 7, so you should aim to use as close to standard views as possible (try using Xcode 5 for a better representation than Xcode 4 if you're not already).
For iOS <= 6, you can detect the version and continue to show them a different UIACtionSheet than iOS 7, or standardize them inline with the changes you make for iOS 7.