HELP! Tile edging where three sides meet!

Hello,

I hope this is an easy one for you.
We are tiling our bathroom at the moment and have come across a small problem. We are not tiling to the ceiling on one side so we have a corner where three sides meet :

1 vertical, 1horizontal across the wall and 1 horizontal going into the window sill.

We have already started to use some quarter circle beading and would love to stick with that (or cause mayhem by taking it out!) but I cannot find anywhere that solves this problem, any way we do it we will either have a make shift rubbish looking filed edge or a sharp point.

Any ideas? What i really need is a small triangular-but-circular bit to glue in this corner!!

I know what you mean. I've only ever seen a straight forward corner trim. I use a dremel to get a nice smooth corner when 3 trims meet. When it's grouted it looks fine.

cheers for the swift response....whats a dremel, is it one of those tiny little files?
And you dont grout the trim do you?!

http://www.dremeleurope.com/dremelocs-uk/Category.jsp?ccat_id=469
I have the 300 series. You could just use sandpaper - that gives a decent enough finish. (finish with a quite a fine grade - maybe 120 grit or you'll get scratch marks showing)
Yes you grout around the trim. Grout the interface between the wall and the trim too.