Yep...got the same problem too - pause/play just wont have it on ICS. I've tried a few ICS ROMs - all got the same issue, sound is clear as bell and next/prev tracks work fine - but not pause/play! But must admit, I've yet to try a MIUI Rom.....suggestions?
ICS is proving a PITA for me. I'm on Wanamlite at the mo and I need Sky Go to work (which it does fine) but on the 4.0.4 ROMs I've tried like Hydrogen, it wont work! Knowing my luck, if I try a MUIU rom and I get pause/play to work on my BT headset - Sky Go won't
Found the following post when doing a search on it:-
Fix Bluetooth headset/headphone controls in Mog for Android 4 (ICS)
I submitted this via Mog Mobile App Support but was shot down and told to submit it as a "feature request" here. The problem is that Bluetooth play and pause controls do not work in the Mog app for Android 4 (ICS). The skip and rewind buttons work just fine, but play and pause are not responsive. Specifically, on my Galaxy Nexus device, I cannot play or pause music using the Bluetooth controls on any Bluetooth headset or headphones. This worked with previous versions of Android.
I have contacted the Android development team about this, and they said that the Play/Pause specification in ICS has changed a bit. And all that is required is a short coding change on your part (and other developers with similar apps).
They even provided the proper coding:
--- DownloadServiceLifecycleSupport.java 2012-03-26 14:46:29.000000000 -0600 +++ DownloadServiceLifecycleSupport.java 2012-03-26 14:44:21.000000000 -0600 @@ -210,6 +210,12 @@
So it looks like there's the answer.... it's just that it may as well be written in Swahili for all the good it does me. Maybe the Devs can implement whatever that means, into the roms (or produce a flashable zip?)
EDIT: Found a temp workaround during more googling.... it's an app called Media Button Router
and seems to do the job on my S2.... HTH somebody else here!