How to send invitation within Outlook for SharePoint Calendar?

I'm trying to create New Meeting Request in Outlook 2010 (It is SharePoint Calendar), when I click send I'm getting the message below; 

This meeting is not in the Calendar folder for this account. Responses to this meeting will not be tallied. Do you know how can I send invitation within Outlook for SharePoint Calendar? I know that I need to create workflow to do it within SharePoint, but can't do it within Outlook. 

Thanks

Dan