Messing with $post[message] in functions_newpost.php-The quest continues! Form vars?

[MTGDarkness]

One final question, and then I think I'll FINALLY have this stupid issue! (Breakthrough was reached by just scanning all the files that seemed relevant for a comment telling me about "this is where we process posts).
What I did was this:

In file: functions_newpost.php

Find:

PHP Code:

    $post['emailupdate'] = intval($post['emailupdate']);
    $post['rating'] = intval($post['rating']);
    $post['podcastsize'] = intval($post['podcastsize']); 


Add under:

PHP Code:

    $post['message'] = "<stuff>" .$post['message']. "<stuff>"; 


And if you put bbcode in there... it will parse! Hallelujah!

As to my questions...

1. Will a variable that works well in the template (in this case, the aforementioned field variables) work as they are there in the files? Like say I put this string in functions_newpost.php (where I put the last string I mentioned):

PHP Code:

    $post['message'] = $post['field11'].$post['message'].$post['field12']; 


How can I make that work in the file itself?