I usually use a slightly different method.  First create the sphere and make have a glow channel using the multiply function.  Source 1 should be the color you want the glow to be, and the second source a value mode either 1-100 or 1-1000 depending on just how bright you want it to look.  Note that high values will wash out the color too much so stick with something between 50 and 60.

Next I create a bulb light and center it inside the ball.  This works a bit better than aura because it also creates a more realistic indirect lighting element on nearby objects and allows the glow to cast shadows.  Use the light sphere effect on the effects tab to do the aura itself.   The only caveat is that you need to make sure thelight source is centered inside the sphere you create.  It then helps to group them in case you need to move them as a unit better.

Some folks like to use anything glows but I don't like the extra amount of memory it uses.  It also seems to slow down renders because the system has to determine it's geometry on the fly.

I hope this helps.

Rich
(Sparrownightmare)