I typically try to avoid this as to avoid confusing 'icon' and 'name' recognition.  When you start mixing the two, it becomes tricky to keep a 'strong identity'.  Example, see this variation below.  While it is somewhat recognizable, it's not overly intuitive if your not familiar with the name already.

http://i.xomf.com/drbjd.png

I also played around a little bit with wrapping 'ORA' or 'ora' alongside the circle, like so:

http://i.xomf.com/ndxpl.png

And finally, I tried something a little different again.  I like it.

http://i.xomf.com/lgzkd.png

~ Regards