helmet communicator

I need to use a mobile (vs HT) on my motorcycle for greater TX power. I have a Yaesu FTM-500 but I can't find a way to get the RX/TX to my helmet. Any suggestions? I read a lot about the Sena SR-10 (Bluetooth) but it's old, expensive, hard-to-find tech for which I could find no compatibility...

So, I was doing some reading and came upon some old threads that talked about Nextel Direct Talk (Not Direct Connect) where the phones have the ability to go off network and talk directly over the 900mhz ISM band frequencies. First off I had no idea that some of these iDen phones did that, but...