Well, my S9/N4 Sacred Statue with a Spell Focus just enslaved all of Bogus' squad, (Except for the human warrior mage, who was killed by the others) so it can't be too hard to make it work. The Troll Mage resisted the first one, but succumbed to the second just before successfully routing. That and, under the spell description, it just says 'Magic Resistance negates', which is what Soul Slay says unless I'm mistaken. If it was easier to resist, it would say "Magic resistance negates easilly".
Guess what the N4 is for.
