Unfortunately it looks like there's another issue with remastering Ubuntu 15.04 in Customizer.

After remastering Ubuntu 15.04 on an Ubuntu 15.04 host system with the latest version of Customizer from the master branch, Internet connectivity fails, at least when using the Live DVD/USB. Although I was able to connect to a Wifi network, I couldn't get an Internet connection using it. I have checked the Wifi network and have made sure that a stable connection to the Internet was present. I have also checked that it wasn't an issue with Firefox, since no app which connects to the Internet works (eg. Software Center, Totem Video Player).

I haven't made an installation of the remastered distro to confirm whether an Internet connection is possible on a native install, but I will keep you posted when I do.

I have tried remastering the .iso file without any modifications (Open Customizer > Select ISO [ubuntu-15.04-desktop-amd64.iso] > Rebuild ISO) on an unmodified host (Installed Ubuntu 15.04 and Customizer with its dependencies only) with the same results.

I have only tested this on 64 bit remasters. I haven't had the chance to test in with 32 bit remasters yet.