Life drain doesn't work with siphoning wand (power siphon)

maybe i'm a bit dumb but with the wording of Power Siphon i think it should

"Attempts to rip the lifeforce from an enemy. Enemies within Culling range will be highlighted and instantly killed on Hit, granting a Power Charge. Can only target Enemies in Culling range."

so i should regenerate 12% life from Life drain support "Recover 12% of Life over four seconds when Supported Skills Cull an Enemy"

I also came looking to see if anyone else noticed this. I can't see why they wouldn't work together.