optical/toslink 3 way switch for astro a50s?

http://www.amazon.com/Control-Audio-Selector-Switcher-Splitter/dp/B003C15798/ref=sr_1_3?ie=UTF8&qid=1360748647&sr=8-3&keywords=toslink+ir+switch

Something like this. Four inputs, two outputs, with IR support for your universal remote. It lets you spit out audio to both your headphones and receiver, and control it with the included remote. Ideally you'll also have a Harmony remote that you can just add this switcher to your activities. Instead of three (HTPC, BD, 360) activities, you'd run six activities total. One each for receiver and headphone use, such as "360 3312" and "360 headphone".

Or you hook up the heaphones to the stereo analog out of the receiver, and let the receiver handle the downmixing of surround to a pair of headphone speakers instead of the A50s handling the downmix from six to two speakers.

I'm not a headphone person myself though. You may want to hop in to the giant headphone thread in the Xbox 360 section and see what those guys say.

This is what I use. Works great.

http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10423&cs_id=1042302&p_id=2946&seq=1&format=2