The MX record is listed under MX Record Configuration and should be similar to the one below:
- DNS Record Type: MX
- Host: yourdomain.com
- MX server: 442368421.pamx1.hotmail.com
- TTL: 3600 or 1 hour
- Priority: 0 (or High priority)
Then all you need to do is point your MX record to that of Windows Live and allow a few hours for the DNS change to propagate.