Trying to customize the comments template from TwentyTen

This is basically what Im trying to do:
https://img263.imageshack.us/img263/1334/picture1copy.png

I can already style most of the comments the way my mockup looks from simply using css on the existing styles, but I need to change the outputted html from the comment list in order to be able to add the little background image icons for the user name, date, and time…

Is this possible?

the code of the comment output is in functions.php of twenty ten; from line 300
(actually starts at line 289 with:

if ( ! function_exists( 'twentyten_comment' ) ) :
/**
 * Template for comments and pingbacks.
 *
 * To override this walker in a child theme without modifying the comments template
 * simply create your own twentyten_comment(), and that function will be used instead.
 *
 * Used as a callback by wp_list_comments() for displaying the comments.
 *
 * @since Twenty Ten 1.0
 */
function twentyten_comment( $comment, $args, $depth ) {
	$GLOBALS['comment'] = $comment;
...
...
...

Thanks, I previously found the template inside the functions.php a while back, my issue is Im not too sure how to go about altering that php in order to inject my own custom html so that it can look the way my mockup does.

I basically need some help on how to make a custom callback so that I can create my own comment that isnt verbatim to the way it gets outputted right now. This is normally pretty easy stuff if I had to do this in the loop since I just markup my html and then plug in the appropriate wordpress tags to dynamically fill the rest of the content, however I dont know php enough to muck around in the functions template to re-arrange stuff or moreso completely alter it from its original look which is what I want to do.

how to make a custom callback

this area in functions.php is the custom callback –
called here in comments.php:

<ol class="commentlist">
			<?php
				/* Loop through and list the comments. Tell wp_list_comments()
				 * to use twentyten_comment() to format the comments.
				 * If you want to overload this in a child theme then you can
				 * define twentyten_comment() and that will be used instead.
				 * See twentyten_comment() in twentyten/functions.php for more.
				 */
				wp_list_comments( array( 'callback' => 'twentyten_comment' ) );
			?>
		</ol>

you can write your own custom callback, add it to functions.php, and then change the callback name in the eline above.

Thanks for baring with me here Alchymyth…
Im aware of where the callback is and how to change the name, etc…
The part Im in need of some help with however is changing the actual custom callback around…I framed the comment the way I want via html/css perfectly fine, but when I tried to remove certain parts of the callback and place my new markup in there it broke the theme….

Basically looking for an example Custom Callback, FULLY COMMENTED OUT to explain whats happening step by step in each part. Ill be able to sort the rest out from there if I can reference something like that basically.
Thanks

In case anyone else is having trouble sorting out the same thing, here is a link to probably the only useful tutorial/article out there on the subject and it helped me out quite a bit:
https://www.net-cake.com/creating-your-own-wordpress-comment-form