Sorry to ask a dumb question, seeing is how the topic is how to get Bluetooth tethering to work, but...
Why would anyone want to tether either a 3G or 4G capable phone to a WiFi Xoom via Bluetooth. Is it not possible to tether via USB?
Prior to getting my Xoom (wireless) I used to use PdaNet on my Droid X phone to tether to my laptop.
Bluetooth tethering was only ever a complete pain in the ass, and even when I could get it working, the poor transmission rate via Bluetooth was insufferable.
On the other hand, tethering via USB was always quick to hook-up, usually worked well, and allowed for 3G type transfer speed.
I can understand using Bluetooth if it is not possible to do it using USB, but it USB tethering is a viable option, is the trade-off of poor performance really worth the ability to not have to use a cable between the devices?