QTVR pano Changing the sky

Hello I produce a pano and the sky are not interesting. How may change a sky in a pano, Blend 2 pano one with a only a sky ok, in this case with what soft. Or in PSD frame by frame, I try to take the same amount of picture in pano displacement of the sky, put over the base picture. It is hard to give a std quality, the cloud dont match that look strange. Some one have an idea?
"I am losting my Latin" in french. Thanks Rene Beaumier