Date Spans in Calc

Hi (Stu?)

I'm trying to find the number of days spanned by two dates.  For example:

Date1:  18/12/12 22:00

Date2:  19/12/12 02:00

Now at first sight I thought timespan would do this but this shows the days between the two dates ie value of 1 if i round up the above example rather than the value 2 I expected (as it spans 2 days)

If this was SQL a DateDiff with interval of Day would probably crack this.   I know DateDiff is also in VB Net but C# and Boo i'm not so sure.

I want something that returns a value of 2 in the above example (not 1)!

Any ideas "Stuguru";  oh grand calc master? 

Julian