user management

Hello,

I would like to use puppet to manage my user accounts.  I also have a 
requirement to do things like password aging on the systems, and 
enforcing strong passwords.

I can create a user just fine with the user class and have it assign a 
password to the account.  If I change the password on the local machine, 
puppet will reset it to the password specified in my user class.  Is 
there a built in way I can tell puppet to only set the password one 
time, and allow the system to manage it at that point?

I'm running centos5 with the ruby-shadow libs installed, and puppet 0.23.2

Thanks
-Adam