You can create a Microsoft account using your @connect.ust.hk email address. Go to
https://signup.live.com/signup.aspx and enter your
[email protected] email address in the username field and complete all the other requested information. You will be asked to verify your new Microsoft account.
After that sign in to your Office365 account. Look in the "Services and Products". Under Skype, click activate the world minutes. On the next page, if you already have a Skype account, sign in to your account. If you don’t have Skype, click "Create Skype account" and follow the instructions.
After you have signed in to Skype, activation is complete. It may take a few minutes for the Skype world minutes to show up, but you should see a message at the top of the screen when it is finished. Then you are ready to make calls.
Hope this works for you.