Users avatar in Revolution blog

I’ve just implemented a Revolution blog using the tutorial http://rtfm.modx.com/display/revolution20/Creating+a+Blog+in+MODx+Revolution and I’m impressed.

On comments it’s using an avatar. How do I set this avatar per user? I’ve seen mention of gravatar http://modxcms.com/extras/package/?package=192 but this isn’t available as a package from modx manager.

Did you have any luck with the manual install yet? Looks that it isn’t that hard to get it working...
Please let us know if you succeeded!