I was able to get the beam bolts to go though to the top of the beam and still having the traveller track span the width of the beam by carefully routing a small section out of the bottom of the track (harken track) so that the track can sit over the top of the bolt heads. It means that you need to remove the traveller track to tighten the bolts, but it may be a stronger way of mounting the beam. If you do it this way, a piece of SS tube for the bolts to go through between the top and bottom of the alu beam stops the alu beam being crushed when you tighten the bolts.