Can i sum time fields?? (i expect that yes....)

Hi everybody.

I'm a visual basic programmer, actually, visual studio 2005, now i beginning with crystal report for visual studio 2005, nice and easy to use with the wizard, but,,, if i want to do something i little bit complex i can't find a manual for beginners.

Now Iu2019m trying to do a report that list fields from a typed dataset, that dataset contains same datetime fields i.e. 1:30 , I put that fields in the details region, all it's ok, but the problem became when i try to sum all the times and totalize then. The reason (i supposed) it's that the4 crystal can't sum time fields.

Thinking about this, i suppose that i can do something with code but i can't find nothing about this, Can anybody tell me where is a manual to code in crystal report?

Well, if somebody have any idea please tell me.