Setting up a bluetooth PAN and NAP without password and possibly using bluetooth low energy (BT 4.0)

Hi!

I would like to set up a Bluetooth NAP to facilitate a PAN at home. I 
have managed previously, but it has been quite unstable and 
authenticated host have been needed to be removed and then re-added from 
time to time. So I stopped using it because there was to much hassle. 
Now I would like to give it another go.  Two questions:

1. Is it possible to set up a PAN/NAP that does not require a password, 
ie. don't require any authentication? How?

2. The new bluetooth low energy present in Bluetooth 4.0, can it be used 
for PAN/NAP?

I am an Ubuntu user, so if you want to be Ubunutu specific I don't mind.

Thanks in advance!