[Plugin: Special Recent Posts] add post-category css class?

I need to dynamically add the post category as a CSS class to each SRP post item. There is no immediate option to do that in srp and srp PRO. Any idea how to do that?

For example:

<div class="srp-widget-container">
<h3 class="widget-title"></h3>
<div id="srp-singlepost-1" class="THE-POST-CATEGORY srp-widget-singlepost srp-single-column">
<div class="srp-thumbnail-box">
<a class="srp-widget-thmblink" title="Bellezza e reazione" href="http://www.alfabeta2.it/2012/02/17/bellezza-e-reazione/">
<img class="srp-widget-thmb" alt="Bellezza e reazione" src="http://www.alfabeta2.it/wp-content/plugins/special-recent-posts/cache/MTAwMTAwbm9lbmVsMi1maXhlZC00MTV4NTAwLWN1dA==.jpg">
</a>
</div>
<div class="srp-content-box">
<br style="clear:both; height: 0px;">
</div>

http://ww.wp.xz.cn/extend/plugins/special-recent-posts/