I also feel one should not do anything special, because the activity at the soft palate is a reflex of what happens at the larynx, just like the tongue is a mirror of the emission. If the larynx drops in the right way, with an U vowel form at the pharynx and the light mechanism takes charge, then the soft palate activates to resist the column of air and goes forward to open the way at the back to the resonance cavities in the cranium. Lili Lehmann talks about this phenomenon in her book. The resonance migrates from the hard palate up. At first, one gets a little dizzy with this sensation.