I’ve been using Windows Live Mail for my domain mail for a while now via the Custom Domains service (now called Windows Live Admin Center). I recently upgraded to a Windows Mobile 6 smartphone (from WM5) and couldn’t figure out how to get my mail account set up. It turns out you have to sort of trick it to make it happen. When you add an account, enter a ”hotmail.com” address. That will have it look up settings for hotmail.com accounts. It’ll then ask you again for your email address and that’s when you provide your Custom Domains email address and sign in with your password. Continue on through the wizard and you’ll have it all set up soon after.