new major mode doubts

[Luca Ferrari <fluca1978@infinito.it>]

Hi all,
as an exercise I'm trying to implement my own major mode for a
programming language (dataflex, for what it matters). I'm following
the Mode Tutorial http://emacswiki.org/emacs/ModeTutorial and so far
I've the skeleton of the mode to work for me.
However, I've got a couple of doubts:

1) in the keyword list I specified a regexp for uppercase keywords as follows:

 (defconst dataflex-font-lock-keywords-minimal
  (list
   '("\\<\\(BEGIN\\|E\\(?:LSE\\|ND\\)\\|FOR\\|IF\\|LOOP\\|MOVE\\|||T\\(?:HEN\\|O\\)\\|WHILE\\)\\>"
. font-lock-builtin-face )
   '("\\('\\w*'\\)" . font-lock-variable-name-face) )
  "Main (and minimal) highlighting for the Dataflex mode keywords" )

however my keywords could be camel case (therefore BEGIN, begin, bEgin
are all the same). Do I have to specify upper and lower case words
individually (avoiding the mess of the camel case) or is there a
smarter way to do it (e.g., checking the font lock against lowercased
words)?

2) the commenting is behaving in a strange manner: I've c++ comments,
therefore // .... and so I've defined the following:
(defun dataflex-comment-dwim (arg)
  "Comment (in/out) a Dataflex piece of source code. It is based on comment-dwin
of newcomment.el"
  (interactive "*P")
  (require 'newcomment)
  (let ( (comment-start "//") (comment-end "") )
    (comment-dwim arg)))

but while it works for M-; comment, commenting out  awhole region
causes each line to be included into a couple of // as

a line of code

becoming

// a line of code        //

it seems as it comments out the region and for each line places an
empty comment at the end. Any idea on what I'm missing?

Thanks,
Luca