Convert Datetime data

maybe a silly question, but I have several datetime items with values like:
2017-08-12T15:00:00.000+0200

how can I show the time with the timezone-correction? When I try this in a dummy-widget with HH:mm there is no timezone correction…

HH:mm:ss.Lz

https://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html