If you would like to remove buttons from the Ribbon of SharePoint, you should use something like this in the elements.xml of your custom action:
<?xml version=”1.0″ encoding=”utf-8″?>
In this msdn article you find the details.
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He is Consultant for SharePoint Solutions for collaboration, communication and business processes. He provides his customers applications based on standard features as well as development or combining the power of several microsoft tools like Dynamics CRM. In his free time he tries to collect tipps and worthy experience in this blog.