The /etc/apt/sources.list.d directory is provided in Ubuntu 6.06 LTS to allow packages and administrators to add new respositories to the system without changing the default /etc/apt/sources.list file.
Since all EasyUbuntu needs to do is enable the Universe and Multiverse repositories (should that option be checked in the installer) a suggested file for use in that directory is as follows (please modify as appropriate, I admit I'm new to this!):
/etc/apt/sources.list.d/easyubntu.list:
# This enables the Universe and Multiverse respositories as
# requested during the use of EasyUbuntu. These
# repositories must be enabled for software installed by
# EasyUbuntu to recieve patches.
#
# The EasyUbuntu homepage is at:
# http://easyubuntu.freecontrib.org/
#
# Please report any bugs on our Launchpad site:
# https://launchpad.net/products/easyubuntu/
#
# Thank you for using EasyUbuntu!
deb http://us.archive.ubuntu.com/ubuntu/ dapper universe multiverse
deb http://packages.freecontrib.org/ubuntu/plf/ dapper free non-free
deb-src http://us.archive.ubuntu.com/ubuntu/ dapper universe multiverse
deb-src http://packages.freecontrib.org/ubuntu/plf/ dapper free non-free
Need to investigate how we are not going to break compatibility with breezy