Hi Davide
Visualizing tracts in 3 views is not directly supported in current version of BrainSuite. But there is an alternate to achieve so. You can use TractConnect (http://neuroimage.usc.edu/neuro/Resources/TractConnect) to generate a mask file for the selected tract. Then if you load the mask file with your 3d image, they will be aligned and visualized in the 3d view.