[Plugin: Special Recent Posts] Show just one random post

I need to show randomly only one post.

I tried to use the following shortcode, but it always returns the last post published.

[srp srp_number_post_option=’1′ srp_orderby_post_option=’rand’]

Is it possible to show just one post, picked randomly?

Thanks!

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