Time Calculation Problem

Hi,

I can not get a time calculation to work. It's probably something simple I'm missing:

...

Case $msg = $settime
                $dt = GUICtrlRead (11)
                ;$tm = GUICtrlRead (12)
                $tm = "15:07:52"
                $dt = StringStripWS($dt, 3)
                $tm = StringStripWS($tm, 3)
                $dtrgex = StringRegExpReplace($dt, '(\d{1,2})/(\d{1,2})/(\d{4})', '$3/$2/$1 ')

                ConsoleWrite("|" & $dtrgex & $tm & "|") ; future time

                $DateCalc = _DateDiff('s', _NowCalc(), $dtrgex & ' ' & $tm)

                ;$DateCalc = _DateDiff('s', _DateTimeFormat(_NowCalc(), 2) & ' ' & _DateTimeFormat(_NowCalc(), 5), $dtrgex & ' ' & $tm) ; this didn't work either...

                ConsoleWrite("DateCalc: " & $DateCalc & @LF)

I'm getting 0 for the date calculation. Obviously I'm doing something wrong. I would be grateful for help.

Console:

|2013/9/7 15:07:52|
DateCalc: 0