Vayne is a very special case - as if Hurricane worked with Silver Bolts - Vayne would never get a Silver Bolts proc ever gain.
If it becomes a major problem we'll just have to be more careful on tooltips and labelling with Hurricane. It's a problem that's been solved before. Hurricane is essentially an 'On Attack, fires 3 bolts that apply all your On Striking' modifiers, in Diablo 2 parlance, so I know it's solveable.
Then it would be like every other on-hit effect instead of following arbitrary rules of its own.
If that makes it too strong, then it should be nerfed to be brought in line with other on-hit effects like Blighted Quiver and Toxic Shot.
I notice how this item's introduction coincided with the removal of Maldred's Bloodrazor. Hurricane alone would have made MBR a great item. If Hurricane was coming, there was no reason to remove MBR because Hurricane's very existence makes MBR good.