WP RSS Multi-Importer options not working

Hi all

I’m new at wordpress. I have created a new site and I implemented the following plugin in my pages to displayed some RSS feeds: WP RSS Multi-Importer.
This work OK. However, the problem I’m having is with the options at the moment to customize the way the data is displayed. For example, I’d like to have the headlines of each feed in bold and with a Font size of 20px. So, I did the following:

wp_rss_multi_importer hdsize="20px" hdweight="500"]

But, it doesn’t work. I mean the headline is always the same

Does anyone know how I can change it?

Thans in advacne