I have tried to achieve what your looking to do and sadly haven’t been able to at this stage.
The issue in pushing these values into the gui, is that the controls don’t allow usage of properties. As you have experienced they simply revert to default dates when text is entered.
Also when assigning the values via script it seems we have a conversion issue. Running the following in the before script of the “Event Log - Search” action
Works only if the dates are full dates and contain no hour, minutes, or seconds components. This is due to the query on the event log requiring the date format to be “yyyymmddhhnnss.zzz000+660” where the +660 is the GMT time zone (in minutes) of the request. This formatting is ignored at present when converting dates to the string format for usage in the query.
I have logged this as something to be fixed in FinalBuilder 8. If it is proving to be a show stopper please send a request to support and we will see what we can push into the FinalBuilder 7 action. Sadly each option does mean a potential breaking of backwards compatibility to the action, hence the saving of this until version 8.
In the meantime I suggest getting the full days log, storing it in a variable then trimming out anything not required. Not the best solution, or time efficient, however it should work as a stop gap measure.
Apologies I haven’t been able to get a best result here. Please do email support if this isn’t sufficient and I will work on something in FinalBuilder 7.