Trouble Pairing BT headset to iPhone

I’m having trouble pairing the Plantronics Voyager 855 bluetooth headset to my iPhone 3GS. Several people at another site (http://jeffreyveffer.com/2009/06/18/plantronics-voyager-855-now-working-with-iphone/#comment-210) have said they have been successful pairing these devices. Here is what I've tried: I have BT ON, WiFi OFF. The phone identifies the 855 (8xxPlantronics) within 1-2 seconds, but after 10 minutes, still isn’t paired. To initiate the process, I am turning on the BT setting on the phone and holding the Call Button on the earpiece until it flashes Red/Blue. Phone displays the activity icon after the word Devices-next line: 8xx Plantronics Not Paired-next line: Now Discoverable. What am I doing wrong? I’ve tried turning both devices OFF, then back ON, and trying again. Same results. I found that I have to hold my finger on the iPhone screen to keep it from going to sleep. Later, I reset the auto-lock to NEVER. That solved the sleep problem, but not the pairing. Each pairing attempt has been only with the single earpiece. I haven't tried pairing with the stereo headset tethered to the primary headset. I appreciate any help you can provide. I got the 855 through an Amazon promotion–end price $5, after $30 rebate! It's a great deal, unless I can't get the headset to work.