We are using the default Geenhopper workflow and we would like to require a resolution when moving to the resolved status. How do we add this? Currently the resolve issue screen is attached to other workflows (like Jira) but I'm not sure how to attach it the Greenhopper workflow.
Short answer: edit the GreenHopper workflow so it matches the "Jira" workflow.
Longer answer: Workflows, screen schemes and pretty much everything else in Jira are highly-configurable. I infer from your question that you're using the default workflows for your Jira/Greenhopper instance. Without having more detailed information about your specific needs it's hard to come up with a step-by-step answer but I can point you in a direction. Start by reading Getting started with Jira OnDemand. That will give you the basics on creating custom workflows. My guess is that you need to add the resolution screen to the Issue Type Screen Scheme for your project and associate it with the "Resolve" step in the GreenHopper workflow. If all that's gibberish to you then start with the stock Jira documentation. It'll tell you how to get started with customizing workflows. Chill, it's not that hard and the documentation is really good.