Yes but I can't find any documentation for it. It's not intuitive. I tried right-clicking on an image and selecting "Optimize viewpoint", which adds a projection icon to the image but doesn't change it in any way. Then if I right-click again and choose "Local-optimize image" it does get changed. The result wasn't good though.
I'm having hell trying to get fisheye nadir shots to align well.
Render cubefaces (KRPano droplet), take the down face which shows the Nadir as planar projektion.
Here you can:
1) edit the Nadir hole by retouching it in Photoshop.
2) fill in your Nadir shot - of course you need to plan-project it first
I prefer to retouch it with the stamp-tool - because i usually take longer lenses with which Nadir shots are impossible to do.