Line Graph - Line Breaks

Hello all, this is my first post as I have found something that I havne't been able to research on the web.

I am using Office XP and I know that in past versions this was not an issue.

I am having a problem breaking a line graph in a chart. I used to be able to select the section of line between two points and go to 'Format Data Point' and select "None" for line type. In office xp when I do this it joins the line to the following datapoint which is not what I want at all. If however I check the smoothed line option it actually works. I don't like the look of this especially when I have a 0 value and it looks like the line dips below the 0 point on the y-axis. And I don't like the look of the smoothed line.

Does anyone know if it's possible to set the line type as None for one section and not have it auto join the line to the next point?

I have attached 3 pictures to show what I mean.