How can I debug CRM 2011 activity workflow with plugin registration tool?

I've been doing this with plug-in and it's really useful stuff cause you don't need be attached to IIS process.
This tutorial explain how to do that locally:  http://msdn.microsoft.com/en-us/library/hh372952.aspx

Now, I'm trying to debug CRM 2011 activity workflow with plugin registration tool but dind't find any way to do that because I don't know workflows.

Thanks!