We configured iis to use a custom error page and then wrote a custom 404 error page in asp that read a list in the dnn database so it could redirect based on settings the customer defined in a dnn list. 

see cofes.com/2003, cofes.com/2004 for it in action

mj

Do you know old style asp? My error page is just a standard asp page that redirects based on data from the database.  You could hardcode the redirects in the asp page.  To make it run you just tell IIS to load that page when a 404 error has occured.  It can't be an aspx page or dnn will try to handle it. 

does that make sense?  There are many sites around that will hepl with asp.  Search google.  I haven't used much asp recently.  I learned it from books and some trial and a lot of errors.

mj