It might be the UV mapping that's causing the split, so you probably can't prevent it because the edge of the UV data is causing the split (Each vert in a mesh holds the UV data, so if a vert is needed for each side of a UV map it needs to be split in 2) - you could try sphere mapping the mesh, but I suppose it depends on what you want to do with it.
If you imagine your sphere is an orange, and your texture is a piece of paper, lets say with a map of the earth on it. You can wrap your orange in the paper to make a model of earth - but it will always have an edge down the middle where the paper meets - meaning it will never be a complete shape - the same is true of your sphere to some extent. I'm not sure if there is a mapping method that can fix it - they all tend to have seam(s) in some fashion or other.
In DBPro, you can set the smoothing manually to hide object defects though, SET OBJECT SMOOTHING Obj,100 should do the trick.
Van-B
I laugh in the face of fate!
