How to Customize the Document Set Ribbon

In this article, we will extend that sample by adding a new menu to download all files in the Document Set, check out selected files, check in selected files and send selected files as links.  We will walk through the example, and we will also provide a finished program and scripts that you can use to upload in your SharePoint server.

Here is Full Blog :

http://community.bamboosolutions.com/blogs/sharepoint-2010/archive/2010/11/12/sharepoint-2010-cookbook-customize-the-document-set-ribbon.aspx