Using PlayFab to purchase Steam items

Hi.

I'm looking to use PlayFab to purchase items on Steam, so that it adds it to the players inventory on Steam;

I have steam linking done, I've setup all the PlayFab purchasing flow using Steam as a purchase provider, which uses the players current steam wallet to Start, PayFor, Complete and Confirm purchasing. But now I want to use the players virtual currencies in their PlayFab account, to purchase an Item through Steam so that it does a Purchase or Exchange request through the Steamworks API, and adds items into their Steam inventory. I've setup the whole Inventory and Store Services for the game on Steam side.

Is there any way at all that I get PlayFab to use Virtual Currency or the consuming of an Item in a players PlayFab Inventory to act as the currency/payment method for granting/purchasing an Item in Steam? Or does steam only allow purchasing of items using the steam wallet?