editor.action.copyLinesDownAction mapping to ctrl+alt+j

[Metaphysics0]

In vscode, pressing alt+shift+up (or down) copies the current selected code and duplicates it above or below.

Has anyone been able to map this command to a vim keybinding?
I've tried everything

What I want to do is this:

"vim.visualModeKeyBindings": [
    {
      "before": ["alt+shift+j"],
      "commands": ["editor.action.copyLinesDownAction"]
    },
        {
      "before": ["alt+shift+k"],
      "commands": ["editor.action.copyLinesUpAction"]
    }
  ],

this does not work.
However, doing this works

"vim.visualModeKeyBindings": [
  {
    "before": ["<Leader>", "j"],
    "commands": ["editor.action.copyLinesDownAction"]
  },
      {
    "before": ["<Leader>", "k"],
    "commands": ["editor.action.copyLinesUpAction"]
  }
],

I don't want to use the leader key though, and would like to just use alt + shift + j ( / k)

[elzup]

use keybinding.json works

  {
    "key": "alt+shift+j",
    "command": "editor.action.copyLinesDownAction",
    "when": "editorTextFocus && !editorReadonly && vim.active && vim.mode == 'Visual' || vim.mode == 'VisualLine'"
  },
  {
    "key": "alt+shift+k",
    "command": "editor.action.copyLinesUpAction",
    "when": "editorTextFocus && !editorReadonly && vim.active && vim.mode == 'Visual' || vim.mode == 'VisualLine'"
  }

by settings.json 's vim.visualModeKeyBindings I couldn't too