I am trying to create a spreadsheet which totals times spent on the phone.

I have formatted the cells as [h]:mm:ss.

The problem I have is that if the time I paste in in less than 1 hour then
Excel misses of the leading 0 and formats as such :mm:ss.

When I try to total the columns, it ignores the cells formated as above. If
I manually enter the leading 0, it stays.

How do I display a leading zero, or, add one in if the value I paste in
doesn't have one.

Thanks in advance