Requesting Help with ODBC and DSN

Hello everybody from Argentina!
I will try to explain to you my problem with DSN and ODBC under Ubuntu
I have a proprietary application running under windows 2000 sp4 and the
latest sql server application.
My problem is that I've installed Ubuntu in a workstation and it's hard
to me to configure the System DSN. Maybe I am wrong setting up proper
driver for ODBC in the workstation or I don't know nothing. Anyway I
request from you a proper odbc.ini and odbcinst.ini files configuration.
if it is possible.
For best understand i send attached a configuration of my DSN in
windows, then you can teach me how replace it in Ubuntu.
I have installed unixODBC and freeTDS in my Ubuntu Workstation.

DSN COnfiguration:   ----> (in win Workstation)

* 1st Page
Name: dsnPrincipal
Description: Main Database 
Server: SERVERSQL\AUTOPACK 
 
* 2nd Page
Loggin ID: sa
Password:            (no password)

* 3rd Page
x Change the dafault database ---> (Checked)
  Principal

This is the most important, i guess.
Well that's all, appreciate any kind of help about this.
Sorry my English please

Regards
Alberto