The driver on the official website is compatible only with OSX 10.7/10.8/10.9. There is no information about a 10.10 release.
You can get more information about this issue using the following contact methods:
Sales:
email: sales@mailasail.com
tel: +44 20 70432832
Support:
email: support@mailasail.com
skype: mailasailsupport