It's best that you clip your mic's onto your hat or throw them into the air by any means possible. It is however possible to record from your jersey. Ive done it before =)
I recorded Static-X and Assesino at HOB Anaheim 2 years ago, and it was all under my jersey. Came out pretty good. Maybe a lil clipping because i was young and still didnt know how to use my equipment all that properly, but hey, it doesnt take much outa the quality unless you are in the pit and people are bumping into you, and you are squished. THEN the sound will be lost. I'd wanna keep it up in the air at all times, but if you need to stealth it because of tight security, jersey works decent.