For those who wish to use Thunderbird for their email client and emulate Winmail, you can do so with a little work. I used Winmail as a POP3 client with my messages saved to various folders on the local computer. TB out of the box will try to install itself as a IMAP client which basicly maps the server email folders to the local machine - the messages still reside on the server. If you create folders, they to reside on the server unless you specifically create them as local folders. To do TB with POP3 you need to install manually. As soon as you start the install, you will be asked for your user name/email address and the "wizard" will automatically contact the server and establish a IMAP account. You have to stop the wizard before it can get finished. As soon as it starts click the "stop" button. Then click the manual setup button and go into the tabs and manually set the program for POP3, and giving your email server address, etc. You need to set the SMTP server as well for the outgoing mail. The data is same as for the WINmail accounts tab.
After you get connected (be sure to select the option to let you manually ask to get your mail instead of the default of getting mail automatically when TB starts so you can import all the locally saved old messages first) you can import the contact/address book from winmail. You need to save it from winmail in the comma delimlted form first in a folder where you can find it again or to the desktop.
Then download and install the import/export addon tool for TB here: ImportExportTools
This tool will allow you to import all your folders and saved emails from the Winmail folder under your users directory.
I got all my saved emails complete with attachments back under TB without any problems but they are saved under the Inbox folder which you have to expand in order to see them.