802.1X Port Authentication using unix user/pass

[lists.mailing at surasoft.com]

Hi,
I've looked at the 802.1X Port-Based Authentication HOWTO guide, I have a few
questions.

The guide authenticates using a "users" file which is a formatted text file.
I wish to use the users unix (linux) user name and passwords which I are in
/etc/password and the /etc/shadow which
has the encrypted string for the password.

My Question is:
 Can I follow the guide and trivially make it do what I want?
 I have a feeling somehow what I want to achieve requires the password to be
sent plain text (not CHAP) ... correct?
 BUT is the "plain text" encrypted anyway between the access point and the
wireless node using OpenSSL or if the password was sent plain text can it be
sniffed?

To make life easy...
I want WPA-EAP authentication working, but I want the authentication be against
the Linux username and its password.

Is this possible? Guides and tips welcome

Cheers
Sura