SAP Belize theme not available in choices on SAP GUI 7.5

Hi, I've just installed SAP GUI 7.5 on my Windows laptop and I was expecting to be able to use the new SAP Belize theme. However, it is not available in the choices of themes in the Visual Design section of the Options. I see Blue Crystal, Corbu, Signature, etc... but not Belize. How can I get it ?