[exim] Getting exim to ignore the local domain when sending

Hey all,

I'm having some problems with exim with my setup. Basically I have a VPS running Ubuntu. My mail is being handled via a separate service (fastmail). My MX record is pointing to them. I need the ability to send emails from web scripts which is why I installed exim, unfortunately I have an issue getting exim to look at the MX record for emails to myself

If I try to send an email from my VPS to a non @mcubedsw.com domain name then is sends fine (eg echo "Hello" | mail -s "Test" foo@???). However, if I send an email to an @mcubedsw.com domain then it doesn't send it. Instead it says that it is an "unrouteable address". For example:

exim -bt pilky@???
R: system_aliases for pilky@???
pilky@??? is undeliverable: Unrouteable address

I've tried to remove every reference to mcubedsw.com from config files and spent hours reading docs and googling solutions to no avail. I'm a bit of a reluctant server admin so I'm not exactly teeming with experience. Does anyone have any advice on how to get exim to send emails to my local domain to the server listed in the MX record for it?

Thanks

---------------------------------
Martin Pilkington
Writer of Weird Symbols
pilky@???