Been searching for an answer for this for an hour. I have three accounts in WLM. One of them is not working properly.
FYI I had this same problem when backing up my system last year. I never resolved it and just lived with it. Now I am setting up a new computer and the problem is still here.
When I reply to a message in this account it reverts to sending it with the default email. So it does not include the signiture and does not send from the correct account. The trick is it only does this with the transfered/backed up emails. Since I've setup my new computer and configured the three accounts in WLM I have two new emails in that account. I can send from those just fine and windows recognizes the account I'm sending from and puts in the proper signiture. So it only does it to the "old" emails that I backed up. For some reason WLM is not properly reading those "old" emails and recognizing the account they are from.
Again this happened a year ago but I just lived with it. As after a few days I would be replying to new emails and it would work fine. If I went back and tried to reply to an email that was "old" or "backed up" it would revert to sending with my default email just as my new computer is doing now.
Any WLM geniuses out there?