forwarding mails arlready in Maildirs

[Marlon Anthony Abao]

guys,

is there a way for get the existing mails in the users' Maildirs and 
forward them to a remote address?

i have a client who has a lot of mails and who wants to have these 
forwarded to his other ISP.  i can forward any incoming mails but how do i 
forward his existing mails?  especially those w/ encoded attachments (sigh...).

thanks.

-marlon