[exim] Problems with newsletter sending

Hi...

I try to send Newsletters with exim.
The Newsletter software connets as client to the exim, it uses 1
Connection which puts thounsands of mail into exim an hour.
Now i got the Problem that exim says

2005-05-26 10:04:31 1DbDLz-0002Ud-Dj no immediate delivery: more than 10
messages received in one connection

and than:

rejected MAIL command H=postman.foo.de (postman) [ip here]: too many
messages in one connection

can someone telle me how to fix it?

Thanks

Alex