Developing Thirty Party Controls for RS2005

I want to develop a new report control or extend the existing textbox control in RS2005. Is there any documentation or examples on how to do this?

Thanks,

Check out Teo Lachev's recent MSDN article on the CustomReportItem feature of RS 2005: http://msdn.microsoft.com/msdnmag/issues/06/10/SQLServer2005/default.aspx

-- Robert