Add attachments while creating issue via REST API

[Carsten Stepan]

I already read this post Solved: How to attach a file while creating Issue in JIRA ... (atlassian.com) about creating an issue and adding attachments in one go. The proposed solution here was to first create the issue and afterwards add the attachments. This is what I am currently doing.

However from the createmeta-Endpoint of my instance it seems I could also add attachments while creating the issue:

{
  "startAt": 0,
  "maxResults": 50,
  "total": 16,
  "fields": [
  {
    "required": false,
    "schema": {
      "type": "array",
      "items": "attachment",
      "system": "attachment"
    },
    "name": "Anhang",
    "key": "attachment",
    "hasDefaultValue": false,
    "operations": [
      "set",
      "copy"
    ],
    "fieldId": "attachment"
  }]
}

Is the configuration from the endpoint whrong or how would do that in a single step? I tried it using the following request in curl:

curl -H "Authorization ..." https://myinstance.atlassian.net/rest/api/3/issue -X POST -d '{
    "fields": {
      "project": { "id": "1234" },
      "summary": "my summary",
      "description": "my description",
      "issuetype": { "name": "Story" }
    }
}'

 but unsure how to provide the attchment here (if at all).