ToME: the Tales of Maj'Eyal

I bought access to the Ashes DLC with voratun coins. I would like to have it on steam as well.

I could buy the DLC a second time through steam for this, but I suspect there's another way. I haven't turned anything up through searching. Does anyone here know how?

I believe if you link your Steam account to your te4.org account, it will make it available on Steam.

Right on! The link to add the DLC to steam was in the my account page.