To migrate the data from Thunderbird mailbox to MS Exchange mailbox I would like to suggest Thunderbird to Live Exchange Migration Tool. It is a highly advanced tool recommended by professionals to export Mozilla Thunderbird data in Exchange Server without losing a single character from the mailbox. It is a GUI based application that exports TB to Live Exchange in a few clicks. It provides multiple export options along with file loading options to make a user work easy and accurate.

More info- http://www.thunderbirdtooffice365.com/thunderbird-to-exchange.html