Can't get dateTime strings.

Hi experts,

I’m using IS 4.6 SP2 and Developer 4.6.
I use build-in-service ‘dateTimeBuild’ to get strings of dateTime format.
But I can`t get hour-strings, minute-strings and second-stings.
For example, it becomes following inputs and outputs.

format: yyyyMMddHHmmss

string: 20021210000000 (<- Anytime same!!!)

What do I miss ?