Module Class Suffix Ignored

Hi, I'm using the Follow Us on Twitter module (v 1.2.1) and I need to add a CSS class (customFloatRight) to control its position however when I add a class name in the Module Class Suffix section of the Advanced options (including a preceding space to a register it as a new class) the class is ignored and is not added to the code (I've checked in the browser):

<div class="mod_fuotw">
<a href="*****" target="_blank"><img src="*****" alt="Follow Us On Twitter - Image" title="Follow us on Twitter " width="36" height="36"></a></div>

The Find Us on Facebook module (v 1.4.2) works perfectly with the equivalent settings:

<div class="mod_fuofb customFloatRight">
<a href="********" target="_blank"><img src="********" alt="Facebook Image" title="Visit our Facebook page and become a fan." width="36" height="36"></a></div>

Having double checked settings and compared them between the 2 modules I can not see anything wrong with the configuration.

Could this be a bug in the Follow Us on Twitter module?

Thanks

R