How do you Create a Custom 404 Page?

[kevinpaffrath+ 1]

I would like to create a custom 404 page. How can I make a page serve as my 404 page and then have all non-existing URL's to that page? Thanks! I am using Platform Pro

[Rob 547]

Couldn't you edit the 404 structure that works now? It's relatively easy to drop things onto it via PlatformPro > Template Setup > 404 Error Page (in the drop down list).