Actually this method has been used for over a year already. I am surprised why I could not find another hacker posting this. Anyway, I assume I invented this. To crack it, it is so easy. It works on Mac 10.6.8. I know the steps below are quite hard. If you can wait, i will make a program to run that automatically. =]
download and install mbox mail for mac 1.0.2 from fluentfactory.com
add "127.0.0.1 secure.mfluent.com" to /etc/host
edit value of LicenseTrialDays to 3650
open /Library/Application Support/FluentFactory/mBoxMail/mbox.dat with any Sqlite3 manager
edit value of table->properties->c_date to many years later like 2050
finished and enjoy!