Cut a triangular piece out of the fairing on each side, between the vertical stab and the horizontal stab. Get the fairing to fit around the empennage components. Then, lay up 1 ply of bid onto your fuselage (covered of course) and flox the fairing onto the layup. While wet, apply another 1 ply bid layout on the top of the fairing around the openings that you cut out, overlapping the layup on the sides of the fairing about an inch. This ties the bottom and top layups together. Once dry, fill with microballons and you should be good to go.