Easypano Panoweaver is capable of stitching the images produced with your suggested combination. I.E: Nikon 5000 and Samyang 8mm Fisheye Lens. Panoweaver classes the images as "fullframe".

Shooting procedure best suited is 4 to 6 rotational shots at -5 degrees tilt down and 1 or 2 Zenith/Up shots at +65 or +70 degrees tilt up (180 degrees opposed if shooting 2 Zenith shots) 1x (hand held or tilted tripod) offset Nadir/Down shot to cover the tripod area if desired.

Of course there are other stitching software programs also, but seeing this is Easypano's forum we'll stick with Panoweaver.

Regards, Smooth