Send appointment invite to clients

Hi all,

I have encountered an issue when sending appointment invite to external users. If I manually create a meeting in Outlook, it will send an invite to all participants. Does anyone know how to send invite in CRM instead of Outlook. I initially tried to use workflow to send meeting confirmation email to our clients, but there was a bug in the time zone of the email. If send an invite, it will automatically convert the meeting time to the receivers but the workflow does not. 

Thanks