New Imac - Mail changes dates on imported mail from Eudora

[pbridges]

When I import a mail box from Eudora into Apple Mail it changes the date to the current date and time
on all mail that I had sent in the box, but leaves the correct date and time on received mail.

This is a nuisance as I lose the actual date I sent the mail.

It did it on both OS 10.6.4 and 10.3.9