period in name

[former03 | Baltasar Cevc]

No,
you must use unixhierarchysep - otherwise the dot is the delimiter, 
meaning that you would have three levels of mailboxes with this (user 
-> first -> last).
I don't think you will experience any problems - any server that uses 
names with dots has to change this and I think IMAP server and client 
explicitly agree about the delimiter sign they use...
Baltasar