how to select interactively the time in org-time-stamp

[Uwe Brauer]

Hi 

The documentation states, and I quote 


,----
| (org-time-stamp ARG &optional INACTIVE)
| 
| Prompt for a date/time and insert a time stamp.
| 
| If the user specifies a time like HH:MM or if this command is
| called with at least one prefix argument, the time stamp contains
| the date and the time.  Otherwise, only the date is included.
`----

So I run 
C-u C-c .

And org proposes me the date and time of that moment, I can change the
date, since the calendar pops up, but how I can change *interactively*
time time?

Thanks

Uwe Brauer