[Plugin: RSSImport] Customizing number of items output?

Great plugin! One thing I can’t get it to do, when using shortcodes, it customizing how many items appear. Do I have to edit the actual plugin itself? That is the only way I can get it to change the number of output items. Otherwise using the shortcode, it doesn’t change. No matter what I specify in the shortcode, it just goes by what is specified in the plugin file itself, as to how many items are shown.

Thanks!