How do I use sticky posts for Classified Listings?

I am using a theme that allows sticky posts to be featured on the home page but the custom posts from the classifieds plugin does not have the option to make them sticky posts.

I read this: article: http://codex.wordpress.org/Sticky_Posts and I understand custom posts are not supported by default for the sticky post feature but I am hoping there is a simple way you could tell me how to change that.