CP Upgrade - Custom Error Annoyance

I’ve come across an annoyance with the upgrade of the CP to 3.0

I have a nifty little script that emails me details when a generic server error (500) occurs (can’t connect to MAIL service, data write errors etc).

I had set this up as a custom error on 500 pages. The old ones I’ve added to accounts still work BUT when I went to add one to a new account yesterday all the options for custom errors are for like 500.12, 500.14 etc etc and are for specific circumstances.

Is there any way to add a generic 500 custom error either through the CP or a ticket?

Thanks
Geo