Getting GlobalObjectID from UID(Appointment created from IPhone)

Incase Appointment is created from IPhone i am getting UID as 'FD8436180C594341977272AAB7EF855B0' when listening through service.

http://www.infinitec.de/post/2009/04/13/Searching-a-meeting-with-a-specific-UID-using-Exchange-Web-Services-2007.aspx

If i convert this using above logic i am getting '/YQ2GAxZQ0GXcnKqt++FWw==' as GlobalObjectID.

Using this i am unable to find item through FintItem API.

How to convert this into GlobalObjectID/ how to get equivalent GlobalObjectID.

Thanks

Siva