Creating Custom Addins

I would like to develop an add-in for Crystal Reports 2011. I found some information about creating a Custom Add-in for Crystal Reports 2008 at the following location: http://www.sdn.sap.com/irj/boc/index?rid=/webcontent/uuid/a0884b0f-b186-2b10-2ba8-f457d0c1ebe8 Crystal Reports 2008 .NET C# - Creating Custom Addins Is there an equivalent example for Crystal Reports 2011? Where can I find more documentation on creating add-ins for the Crystal Reports Designer? I have searched but most information I find is for building stand alone .NET solutions and NOT for building add-ins to the Crystal Reports Designer.