[Dovecot] trying to enable features

[Ray]

Hello all,
I'm trying to enable 3 different features in my mail system (postfix, amavisd, 
dovecot).

1)out of office auto reply
2)script execution based on email
3)automatically add disclaimer/signature to outgoing email
(also listed in order of importance to me)

I'm looking for pointers to documentation or instructions. It seems that 1 and 
2 would best be done in dovecot somewhere, while 3 is probably best 
implemented in postfix. (my next step is postfix documentation) 

Can anybody provide any suggestions or pointers to a how to or other 
documentation?
Thanks,
Ray