Difference between dates

Hi experts,

I must calculate the difference between two dates that are separated in DATS and TIMS characteristics in my infocube. For instance, I have the Creation Date in two infoobjects, characteristic DATS and characteristic TIMS, and the Activation Date just like that. I want to calculate the difference between creation date and activation date (activation date - creation date) and present it in days, hours, minutes and seconds. How can I do it?

Thanks in advance.