Users DB and Group/ACL meanings?

Hello,

I am experimenting with rt2 attempting to figure out how most
of it works. Just a few questions.

Written in the section of the docs titled :

“Users and Queues and Scrips, Oh my! (A configuration tutorial)”

   In its default configuration, RT uses an internal users 
   database to keep track of who can access RT and who has
   what rights within the system. 

Does rt provide any other hooks for a users database ? Specifically
we have an established customer database (mysql) that I would like to hook
rt2 into to avoid multiple data sets. Can rt2 do this easily or does
it require major coding ?

While investigating groups and ACL’s starting from a stock config
a queue called network and an unprivileged user were created.
Under the queue’s group ACL’s I granted “Requestor” :

 ShowTicket
 SeeQueue
 ReplyToTicket
 CreateTicket

However the unprivileged user cannot submit a new tickect or even
see the queue from the unprivileged web interface. This does
work when I enable ShowTicket and SeeQueue in the "Everybody"
group for that queue. I am misunderstanding the role of "Requestor"
psuedo group, should it work ? Does this belong in the "Everybody"
group ? Anyone have a good run down the meanings of all the psuedo
groups and rights ?

Also after submitting a ticket in the aforementioned configuration
the message :

  RT Error
 No permission to display that ticket

pops up. The ticket can be viewed no problem from the OpenRequests
listing or entering the ticket id directly.

Have a nice day.
-Jonan Santiago
-Callisia Communications
-http://www.callisia.com