API payload for Invoice Line Creation (DFF)

Summary:

Can anyone share his inputs regarding API for Invoice Line Creation?

I've managed to create Invoice Lines using the following payload:

{
"LineNumber": 2,
"LineAmount": 2212.75,
"DistributionCombination": "10-6192002-6106-000-00000000-0000-0-0",
"AssetCategory": ""

}

Trying to understand how to connect the DFF part

The payload of the "Invoice Line DFF" should be according to this:

    {

        "rel": "child",

        "href": "https://hxn.fa.em2.oraclecloud.com:443/fscmRestApi/resources/11.13.18.05/invoices/300000053631868/child/invoiceLines/00020000000EACED00057708000110D934A11B7C0000000AACED0005770400000002/child/invoiceLineDff",

        "name": "invoiceLineDff",

        "kind": "collection"

    },

Does anyone know how to connect the 2 parts to one payload?
The attributes are global and serve as ATTRIBUTE1, ATTRIBUTE2.

Thanks.