well ok.. you are using a full frame fisheye lens, hence 6 @60 degrees. Then on the 6th clickstop you rotate the camera up and take the zenith image. And on the 6th clickstop you rotate the camera down and take the nadir image. (while the lens is pointed down) look through the view finder... you should see the pan head. That's what you are going to get in your photo.
My guess is that some how.. when you took the photos your nadir image was rotated out of sync with the 6 horizon image.
You might consider placing 3 manual control points between your nadir image and a few of the 6 images. Maybe that will sync up the nadir.
Even with the Sigma 8mm lens.. that does 4 around on the 4th clickstop rotate up take ceiling shot... rotate the camera down... yup I get the panhead in the photo ALSO.
So with the Sigma or your full frame fisheye lens.. you get the same results - pan head in the photo.
So you have probably seen some panoramas with the nadir neat and pretty.. without the pan head in the photo. Ok... Those folks took the extra step.. removed the camera /tripod out of view. Then they hand held the camera at same height and angle [as if tripod were still in place] and took a down shot.. even with their feet in the photo.
Your other option is to take 6 +1 UP stitch that one with a previously created tripod cap that covers the nadir hole. Panoweaver calls this tripod cap image a "Floor" image.
You may want to consider just trying out a sample Easypano tripod cap sample image 'floor'. Its in the \floor folder. If it is their cap fills your hole... then create in photoshop a new 300 x 300 pixel tranparant gif. Meaning its really a transparent background 300x300 .gif with an 295 x 295 raised circle with some text written on it.
Forum Moderator for
EasyPano - Panoweaver