Is it possible to create VBA function programmatically from a VSTO add-in?
1 Answer
This link explains the process for doing what you want via VBA:
http://www.cpearson.com/excel/vbe.aspx
I don't have any experience with VSTO, but the process might map over.
Edit: example here... http://mrvsto.com/2010/04/use-vsto-to-add-vba-code/