BT2 is installed to my hd. Mine already had a .config file there, which I assumed it was the file used to make BT2. You should have one there too. I did follow his advice to a certain degree, and made the backup in /boot.
cp /usr/src/linux/.config /boot/config-`uname -r`
I rebuilt mine with a bluetooth patch from bluez, to get my keyboard to work. Now it works better than it did in windows XP. It's an MS bluetooth keyboard!
Are you sure you need a new kernel?