The TDatetime is nothing more than a Float/Double..
The integer part(Whole) is the number of days, the fraction is the ratio of the day...
so a .5 fraction is half the day..
(24*60*60)*Frac(SomeTime) = the number of seconds so far...
etc..
something for you to think about I guess.
Btw, you should ask those DEV developers why they don't have such functions