Formatting values on DBChart BarSeries

[StevenK]

I have a DBChart set up dynamically according to user selection. In some cases I am plotting a DateTime for the Bar - I am able to set the fact that we are dealing with a DateTime set of values (using DBChart1.Series[x].YValues.DateTime := True). However on doing this the values shown at the top of the bars shows numerics (such as 0.25 for 06:00:00).
How do I set the format of the Values on the bars such that they read the number of hours, minutes and seconds as required(i,e. 01:15:00).
Can anyone point me in the right direction ?
Thanks in advance
Steve