Milter-greylist

Greetings, this is my first post here, so I guess a hello is in order.

I have been using milter-greylist in production environments for a short
time now, and the effect is great.
However there are some addresses i wish to let through since 1. we dont
get much spam using these and 2. they contribute to most of the valid
mail traffic to us.

Since they have sub-hosts I have added lines like
from /.*@.*\.example\.no/
from /.*@.*\.anotherdomain\.no/

It looks like if the address is longer than 31 characters, these rules
are not honored.

Another thing is the error bad mailers get:
Transcript of session follows:
	  Command:  DATA
	  Response: 551 No valid recipients

I think this might be a sendmail issue, but if anyone know if its
possible to change that to something a bit more readable for the end
user with poor it-staff that surely would be appreciated.

-Johnny