problem after converting wma to mp3

Hi there.
Having eventually got mp3tag to work on Linux (having trawled through the forums for an answer), and thereby be able to a large collection of WMA files. Having successfully done this i thought I would convert to mp3 files. However when i checked the converted files tags in Mp3tag, I found that the Album Artist had shifted over to Artist.
Artist - Bjork.(What I had pre-conversion)
Album Artist - Bjork. (What I had pre-conversion)
Artist - Bjork\\Bjork.(What I have post conversion)
Album Artist - blank (What I have post conversion)
I am able to fix the artist so that there is only one name, I can't get the name into the album artist, other than selecting all files per album and doing it manually. Is there a "Formula" for doing this quickly?
Thanks in advance for any help.

Hav a löook at the FAQs
THis tells you how to manipulate the contents of a field
If you have the artist already stored in the field %artist% then copy it to the field %band% (old) or %albumartist% (new): create the action for Albumartist and enter as format string %artist%.

All the superfluous fields can easily bulk-deleted as follows
select all the former wma files,
press Alt-T to get the extended tag dialogue
(in this dialogue you see all the tags that are in any of the files)
Select the one of the superfluous tags after the other and press the delete button for each.
Then press OK.
THis will delete all the selected tags from the files.

Hi there,
Thanks for the reply. It solved my problem. i had read the FAQ's but didn't quite understand. i do now. Many thanks Ohrenkino.