Siphon mana trouble

I've noticed in ladder play you can transfer mana via siphon mana on bloodmage to an ally. I've tried even creating a new map and left everything at default and still cannot transfer mana to allied heros.

Do you guys know what needs to be changed in the object editor to make it work this way.

Edit: It appears that the game data has to be changed from deault to "latest patch". Would there be around this, because it causes some other bugs in my map when I change to latest patch.

Look under advanced options, and check it to true!

Ya, I just found it in gameplay constants and was about to edit my post, but thanks. It was listed as drain which kind of threw me off.

go to the map options and change map type from melle to last version.