Volibear W/Guinsoos [GAMEPLAY]

Buying Guinsoo's Rageblade on Volibear doesn't prock Volibears W stacks so he can't get off a 2 attack bite. I feel as though it should since the stacks are an on-hit affect. What I did to make this happen: Launch League of Legends>sign in>select PLAY>select TRAINING>select PRACTICE TOOL>select Volibear>once in game buy guinsoo's rageblade>attack a minion twice and see that you do not get the extra stack. Please fix this RIOT.