Rescue Disc and UEFI systems

I’m running the latest Avast Free software and I have created rescue disks using both USB and CD (created iso and burnt with Nero)
Both of these boot and scan correctly on a BIOS based PC, but neither of them are recognised as valid boot media on UEFI based PCs. Using VMWare I have tested them on both 32 and 64 bit UEFI environments. Both the USB and CD were created on a pure UEFI PC (i.e. no legacy support enabled).
So how do I get a UEFI bootable rescue disc?

I could fiddle around with my PC settings to enable legacy booting but that causes me some other boot conflicts on my MB. Given that WindowsPE (upon which I believe the rescue CD is based) supports UEFI there should be no reason as to why it is not supported on the rescue CD.