Transistor
Banned
Apple is using the same standard as Microsoft, HTC, LG, Blackberry and Samsung.
No they don't.
Apple has their own signaling standard: http://allaboutwindowsphone.com/flow/item/17561_Jays_AB_headset_for_Windows_Ph.php
If you've gotten Apple specific headsets to work previously, it was probably a fluke.
Sony doesn't have a proprietary headset standard. There is AHJ/CTIA, OMTP, and Apple's own take on AHJ/CTIA.