Exporting ProRes 422 with 8 channels of audio (5.1 + stereo)

Hey I finished a feature documentary and the distributor is asking for a ProRes 422 export of the film with 8 channels of audio. That is, 5.1 surround with stereo mix all included in the same file.

Most of the tutorials I’ve seen on how to do multichannel audio is expired as in I can’t figure out how to setup a 8 channel sequence or tell Premiere that I want to export all 8 channels.

I tried right click on sequence > modify > audio channels to select “adaptive format” but this doesn’t seem to help.

Outrageous that this is so hard to setup if it such a standard request from VOD distributors.