I am very much intrested in your mail system. First I was trying with a hosting service without shell access but now I am trying to install it through a module i got in XOOPS CMS it is like one click install software so much easier for me. But I have a question I had seen your plugin repositry in which was looking for a solution for enabling me to make users signup to mail system, logging in, and changing password. 
I came up with the solution as vqadmin, vqregister, vqsignup and a login manager plugins.
Is there any tutorial to add these plugins to the my existing squirrel mail system .