I just added support for 1.1.8 today. The conversion was a pain and a lot of work!
I hope it works 
any hope for smf 1.1.8 version
Tonight I release a new version that corrected a missing double quote ("). This caused an xhtml validation error.
The error is in the Display.template.php file. This is the corrected (one line of code) version for 2.0 RC1:
<li><a href="', $scripturl, '?action=buyme;u=', $message['member']['id'], '" title="'.$txt['buy_description_icon'] . $message['member']['buy_type']. '"><img src="' . $settings['images_url'] . '/'.$message['member']['buy_icon'].'" alt="'.$txt['buy_description_icon'].$message['member']['buy_type'].'" border="0" /></a></li>';
2.0 beta 4
<li><a href="', $scripturl, '?action=buyme;u=', $message['member']['id'], '" title="Buy me ' . $message['member']['buy_type']. '"><img src="' . $settings['images_url'] . '/'.$message['member']['buy_icon'].'" alt="Buy me ' . $message['member']['buy_type'].'" border="0" /></a></li>';
v. 1.1.8
<a href="', $scripturl, '?action=buyme;u=', $message['member']['id'], '" title="'.$txt['buy_description_icon'] . $message['member']['buy_type']. '"><img src="' . $settings['images_url'] . '/'.$message['member']['buy_icon'].'" alt="'.$txt['buy_description_icon'].$message['member']['buy_type'].'" border="0" /></a>';