Nokia supported the rSAP Bluetooth Profiles since years generously!

Now, with Windows Phone 8 the Lumia 820 and 920 models doesn't support rSAP.

Is this a limitation caused by Microsoft or is it a Nokia decision? I haerd, that the new HTC Phone X8 supports rSAP. So it seems to be possible. But is it a standard function from Microsft Phone 8 or a HTC development and implementation for Phone 8?