[VM] filter mails to imap folders

[user]

Dear all,
since a while I try to achieve a filtering of incomming mails and to 
store these to particular imap folder, e.g. a new and unread message 
with "GMT" in the subject should be stored in imap folder called GMT.
I tried several approaches based on virtual folders, but all failed.
Does anyone here has a running piece of code which does this or 
something similar and would like to share it?
This would be very much appreciated
ingo

ps:(I use emacs 24.2.1 and vm 8.2.0b)