Following the http://books.zkoss.org/wiki/ZK_Developer%27s_Reference/Internationalization/Date_and_Time_Formatting there are 4 types.
As you can see :
- full and short gives only minutes
- long and medium only gives minutes and seconds.
Unable to set the hour with any predefined time format.
If you use the normal styling (HHH:mm:ss), everything works correct.