[Exim] SMTP message termination

Hi,

I'm running exim 3.13 under Redhat 6.1. I've just set exim up using the
eximconfig script to forward all non-local messages to my ISP's smarthost.
However, when exim connects to the ISP's smtp server it hangs and eventually
times out.
Running pcapture reveals that exim is terminating the message with .. on a
single line rather than just a single '.'.
Am I doing something obviously wrong to cause this? Performing exactly the
same steps manually except with a single . works fine and the message is
relayed on.

Cheers,
john