Removeing RE and Prefix

Is there a way to remove old prefix'es ?
I am using :

<SUBJECTSTRIPCODE>
s/^\[sftest\]://;
</SUBJECTSTRIPCODE>


But it don't get subjects like this one :Re: [sftest] Hmm Og var til denne
via WEB
I have a test setup at http://mail.sf.dk/MHonArc/SFtest/

Im using MhonArc 2.5.1 on a ezmlm arkive

Birger Mortensen