You have to fill EVTDAT, EVTTIM, EVTZON instead of REPDAT, REPTIM, REPZON.
EVTXXX fields contain the actual event date -> the date and time on which an event occured.
REPXXX field contain the date and time on which the event has been reported -> this is set to system date/time if initial (so this is not mandatory).
Check on this is done in FM /SAPTRX/CHECK_DATETIME, if you want to debug this.
Best regards, Daniel