[Dovecot] Sieve regex never matches

Hi,

I found the following code on the net which should redirect all mails to another address depending on the time of day (useful for forwarding mails to work):

require ["regex"]; if allof (header :regex "date" "(08|09|10|11|12|13|14|15|16|17):..:..", not header :regex "date" "(sat|sun)") { redirect "address@work>"; keep; }

To check and test I simplified the regex to match all mails within a certain hour:

require ["regex"]; if header :regex "date" "20:..:.." { redirect "user@domain"; keep; }

Both scripts compile fine, but their regex never match. Has anyone an idea why? I'm using Dovecot 1.0.0 on Debian Etch stable.

Frank