I have been trying to use Folders as a means of capturing all information for particular projects but I have run into a problem with captured eMail messages. Is there a way to move captured messages to folders other than Mail Boxes?
There is not, however you can organize the messages using tags in the source list.
EagleFiler 1.4 lets you do this. If you drag a message out of a mailbox, EagleFiler converts it to a .eml file.