Gandi.net Groups

We're using Gandi for email, and IMAP with SSL. We have several domains
with Gandi. However there is a privacy issue:

Current behaviour of Gandi mail: log in to account securely, send mail,
mail shows recipient not your domain/gandi IP but your actual IP of the
computer you are sending from.

Expected behaviour of Gandi mail: log in to account securely, send mail,
mail shows recipient your domain/gandi IP as source (since after all
that is what we are paying for and it identifies us clearly in case of
abuse).

Even Yahoo or Gmail do not do this, the headers do not show the IP of
the sender. In the event of abuse of course they can reveal from their
logs. IN the case of Gandi domain/email owners, the identity would
already be clear from the domain, so please can this be fixed.

The same should apply when using the web interface hosted at Gandi.