[horde] Custom policy for passwd

[Matthew]

I'm trying to set up a policy for passwd, along the lines of:

 >=20 character (eg a four-word passphrase) OR
 >=10 characters, but must include eg upper/lower case, numbers, symbols

I don't think the rules allow this (although I could be missing 
something?). Is there then any way to write my own? It would just be a 
few lines of PHP - but I don't know where it would go. There doesn't 
seem to be a eg before_password_change hook - or is there something like 
that?