Cannot get theme_links__system_main_menu($variables) to fire now matter what i've added the code below to my theme's template.php file. i've cleared the cache too. but this just isn't firing no matter what. i'm not getting any errors either. 

anyone have any experience with this function? i am using a sub-theme of the Adaptive theme. don't know if that has anything to do with it.

function spn_at_links__system_main_menu($variables) {
 echo '&lt;script&gt;alert("sys menu func running")&lt;/script&gt;';
 $html = "&lt;div class='myclass'&gt;";
 $html .= "  &lt;ul&gt;";  
 foreach ($variables['links'] as $link) {
   $html .= "&lt;li&gt;".l($link['title'], $link['path'], $link)."&lt;/li&gt;";
 }
 $html .= "  &lt;/ul&gt;";
 $html .= "&lt;/div&gt;";

 return $html;
} 


yes my theme name is spn_at with an underscore. i have other theme related function working just fine in the template.php file. big thanks for any help w/ this
The Adaptive theme never calls links__system_main_menu from its page.tpl.php file, hence providing an override has no effect and it falls back to theme_links. If you want to override it you will have to provide your own theme suggestion in preprocess hook function.

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