custom code generation,designers

hi,
we develop an "addin project". we want to generate a new project item like as XSD Schema.
our intention is to provide a view which is similar to xml schema document template. we want to drag-drop user controls from toolbox on to this document view , on the code part like xml-schema we want to write xml-code.
we think that we must write IRootDesigner for view and use XmlSerializer for xml-code. but we could not determine which interfaces and classes we must use.And how to implement them?
Thanks...
[533 byte] By [codefund.com] at [2008-2-27]