Migrating from Citadel to Courier/Postfix

I don't know about much about Citadel, but in the past I have set up an 2 imap accounts using Thunderbird and just dragged all the mail from each folder to the other and it moved over. It really depends on how many accounts you have.

I do have a question. Why do you want to switch? I haven't setup a node yet. I'm still deciding if this is the way for me to go. I'm trying all this stuff on a virtualbox so I can learn how to do all this stuff for free. I do know the Courier/Postfix combo is hard to setup.

It is quite hard to setup. However, my user base is growing quite dramatically and Citadel isn't meeting all of our needs. I need a more robust user creation process.

Is anyone aware of a way of doing this? I'm expecting our user base to grow dramatically within the next month and would like to have the month to test/tinker with this with our smaller user base.