How to create a post on a wall in CRM with rest api

Question

I want to post to https://ascend.crm4.dynamics.com/api/data/v8.2/posts to create a Post on a wall.

I have tried the following

{

    "source":2,
    "text":"hello",
    "postregardingid":{
        "regardingobjectid_opportunity@odata.bind": "(0679f081-9f9e-e711-810f-e0071b6660d1)"
    }
}

and a few other attempts, but i still found no way to create a post on the oppotunity wall.

Anyone done this?