START TIME clause

http://dcx.sap.com/index.html#1200/en/dbreference/create-event-statement.html

CREATE EVENT statement

START TIME clause The first scheduled time for each day on which the event is scheduled.
The start-time parameter is a string, and cannot be a variable or an expression such as NOW().

Given above constraint , is there any way to vary the start-time dynamically ?

Example : A user selects a specific time via en external program which in turn can call CREATE Event with that selected time .

Thanks,

Mahesh.