AoE with Glacial Hammer

Hello everyone i have a question about aoe in glacial hammer.

After reading some guides ive noticed that it is possible to use Aoe Support gem (+30% aoe)
BUT just a few minutes before, I got level 40 and applied this gem to Hammer and it didnt work at all !! Ive tried with Mele Splash Support + AoE support, but there was no difference in the atack range.

Does this AoE support even works with GH ? Or the only option is Meele Splash supp ?

Glacial Hammer doesn't do splash damage normally. Supporting it with melee slash is the worse option. You should use a Winter Burial and an other WB or Hrimburn/Hrimsorrow.
Also Increased AoE and Attack range are different. You can get increased weapon and unarmed range on items and some passives.