LibreOffice is available in wheezy and I guess since the release is not that long ago it should also work in squeeze. But I'm not sure if it will work in lenny or a lenny /squeeze mix (which ED is based on).
I'll check that.

@qole:
Do you see any chances to release an image purely based on squeeze anytime soon or do you have a solution for the libncurses5 problem when trying to do a complete dist-upgrade to squeeze?