I have been able to successfully send and receive email using my mx records fr my domain with no problem, well Ok minor hiccup but my isp then gave me instructions on how to set it up, and smooth sailing from then on.
Why I mention the option of being able to use it locally is because Ibelieve that if you purchase the product or are planning to you need to give them a domain name, and am not sure if the domain name has anything to do with the registered product i.e. my.com will result in a serial number generated for that domain, and when I install I configure it to use that domain for such and such ip etc etc..
Time will tell.
Thanks for the input fellas
Bones