I already have this, but I want to maintain the theme for even the Server-Error.aspx page... which is a Sitefinity page. So if a null exception or key cannot be found error happens, the error still looks graceful and has a Sitefinity page.
Would it work to override the base page and handle it in the onerror event? Does that fire when a Sitefinity error happens?.. not sure how to do this.