I have an archive of the old yahoo posts. Here it is:
https://docs.google.com/open?id=0B0bo1325G8EQUUd2VjZuRnBtcHc After opening this page there will be a menu in the left top corner. Choose File, then Download.
After downloading unpack and copy the file into Thunderbird's profile Mail\'Local Folders' folder. Restart Thunderbird and you should see it under your Local Folders'. First access will take a moment as Thunderbird will have to index it first.
There is a glitch with emails reporting html/text and heaving only text... Will have to sort it our on one point.
Marcin