The attached file should do what you asked for.
As you did not provide some sample data I assumed a n x 3 data matrix (columns would be r, phi and positive color values) and created some random data to play with.
You may chose to try different colormaps or create your own to fit your needs. Furthermore you may uncheck "Auto Contour" on the "Special" tab of the 3-D plot Format box and try different values for "Number" according to the maximal number of colors in your plot.
Changing the colormap may make it necessary to change the color of the X-Y backplabe to match the color which is associated with height 0 as this is assumed to be the background (no data).