Hi,
MLO works ok with any open mail servers, such as gmx.com.
Gmail account set up requires additional settings, such as stunel, please see more info here: http://osdir.com/ml/mylifeorganized/2009-12/msg00030.html
While I love mlo, I must say that I don't like all that you do. MLO development is slow sometimes and some other times you offload part of what I would expect one app to natively do to other apps which us, the users, are supposed tu fumble around with, keep multiple instances of different siftwares running on multiple machines, etc.
I'm sorry but I can't congratulate you on all the things you do. It's about time MLO Cloud implements mail reminders sent out from the cloud rather than from the different clients which sometimes may sit behind corporate firewalls, ...