Outlook 2013 connecting to Groupwise 2012 any solution?

I have been looking for an answer to this question, I have a MS exec that has just been hired in a company that I support. He wants his calender and scheduling to work with the outlook 2013 client. They currently have a Groupwise 2012 sp2 server installed. I have looked, but have yet to find an answer.. I just love the MS pricks..