I got the solution from Reto, the VHDL mode owner:

"
You can add the following to your .emacs startup file and viper should
automatically get invoked when opening a vhdl buffer:

(add-hook 'vhdl-mode-hook
      '(lambda ()
        (viper-mode)
        ))

"

Thanks for the help.

----- Original Message ----
From: Lennart Borgman gmail.com>
To: tbt yahoo.com>
Cc: help-gnu-emacs@gnu.org
Sent: Monday, September 8, 2008 2:07:36 AM
Subject: Re: Please help: How to start the VHDL mode in Viper mode automatically?