I have the iPhone 4S and I have been trying to use custom vibrations and I can't seem to get it working. I have it turned on in my settings and I've tried assigning the vibrations to individual contacts and it still will not work. Also I have the "LED flash for alerts" turned on and still not flash. So frustrating I just recently discovered I have these features and I tried to use them and they won't work someone please help! Thank you!