He Kevin,
This should be fairly simple. Here are the settings to manually configure the X-Axis.
I would use something like that to ensure that you don't get intermediate values. I assume you're trying to avoid fractional values. The X-axis needs to be linear, but you can probably use a few Scale Breaks if your data is very sparse. Scale breaks are only available for the Y-Axis, but you should be able to flip your chart. Here is the documentation on scale breaks:
http://www.telerik.com/help/aspnet-ajax/radchart-scale-breaks.html
Hope this helps!
-Gimmik