wordpress comments file

hey guys! So, I have this question:

I'm working with wordpress to make a blog but I'm having a little trouble with the source files for the comments. On the original wordpress theme (TWENTY TEN'S THEME) the generated html code is basically like this:

<ol class="commentlist"> 
<li class="comment even thread-even depth-1" id="li-comment-15"> 
    <div id="comment-15"> 
        <div class="comment-author vcard"> 
            <img alt='' src='http://1.gravatar.com/avatar/1e1122c513d8fa172232b1acafe1cf83?s=40&amp;d=http%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D40&amp;r=G' class='avatar avatar-40 photo' height='40' width='40' />
            <cite class="fn">
                <a href='http://www.webtiago.com' rel='external nofollow' class='url'>John Doe</a>
            </cite>
            <span class="says">says:</span>
        </div><!-- .comment-author .vcard --> 

       开发者_运维百科 <div class="comment-meta commentmetadata">
            <a href="http://localhost/wordpress/wordpress/?p=88#comment-15">26 de January de 2011 at 12:17</a>
        </div><!-- .comment-meta .commentmetadata --> 

        <div class="comment-body">
            <p>Adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nLorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nLorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p> 
        </div> 

    <div class="reply"> 
        <a rel='nofollow' class='comment-reply-link' href='/wordpress/wordpress/?p=88&#038;replytocom=15#respond' onclick='return addComment.moveForm("comment-15", "15", "respond", "88")'>Reply</a>       </div><!-- .reply --> 
    </div><!-- #comment-##  -->
</li> 

so, what i need is to insert a new div between the div with the class 'comment-meta commentmetadata' and the div with class 'comment-body'.

I've already tryied to edit this in the 'comment-template.php' file but with no success (apparently this is not the right file).

Can anyone tell me which the right file is?

Regards! ;)

Wordpress allows you to specify a callback for the comment layout, in case of twentyten it's done like this:

wp_list_comments( array( 'callback' => 'twentyten_comment' ) );

The callback twentyten_comment is defined in functions.php.