Block displaying in 'content' region of admin theme?
According to this comment, you can also specify the theme. I haven't tried it -- let us know if it works!


  There's also a theme key-value pair: 


'exposed_order' =&gt; array(
'info' =&gt; t('Exposed commerce order filter'),
'theme' =&gt; $admin_theme,
'region' =&gt; 'content',
'pages' =&gt; ORDER_MENU_LINK,
'status' =&gt; 1,
'visibility' =&gt; 1,
),