Custom Error after validating through an API

[ngw]

Hello, I'm having problems using elm-form with a custom API to validate one of my fields. My solution ATM "kinda" works but I think that an example on the documentation for this very common situation would be beneficial, once I have this working properly I'll add it to the example and docs.

update : Message -> Model -> (Model, Cmd Message)
update message ({ form } as model) =
  case message of
    ValidateEmailUniqueness response ->
      case response of
        Ok _ ->
          ( { model | emailTaken = False }, Cmd.none )
        Err _ ->
          ( { model | emailTaken = True }, Cmd.none )

This is how I "manually" set a random Boolean on my model, and the part that probably needs updating as it's not using elm-form as it should (it's not using it at all actually).
The HTTP validation is actually triggered using elm-form:

Form.Input "user[email]" Form.Text (Form.Field.String string) ->
  let
    emailField = Form.getFieldAsString "user[email]" form_
    request = emailValidationRequest emailField.value
  in
    case emailField.error of
      Nothing ->
        ({ model | form = form_ }, Http.send ValidateEmailUniqueness request)
      _ ->
        ({ model | form = form_ }, Cmd.none)

I think the main problem here is that I'm not able to put my work into how elm-form validation works, for example here:

(field "user[email]" (email |> andThen nonEmpty))

Main problem obviously is that even when emailTaken is True I can submit the form.
Any suffestion on how to accomplish this?