How to use default feeds "_Main [placeholder type] feed" when there are no extensions in the account?

Hi.
My problem is that I need to use only default adwords feeds. They appear when user creates an extension through the UI with the name like "_Main callout feed" or "_Main sitelink feed". Until then this feeds are not visible in the Shared Library / Business data section and I can't get them through the API:

$feedService = $user->GetService('FeedService', self::ADWORDS_VERSION);
$selector = new \Selector();
$selector->fields = ['Id', 'Name', 'Attributes', 'FeedStatus'];
$feeds = $feedService->get($selector);

API doesn't allow to create feeds with such name because of "_" symbol and I get FeedError.INVALID_FEED_NAME error:

$textAttribute = new \FeedAttribute();
$textAttribute->type = self::EXT_ATTR_TYPE_STRING;
$textAttribute->name = 'Callout Text';
$feed = new \Feed();
$feed->name = "_Main callout feed";
$feed->attributes = [$textAttribute];
$feed->origin = 'USER';
$operation = new \FeedOperation();
$operation->operator = 'ADD';
$operation->operand = $feed;
$operations = [$operation];

When I try to use "ADWORDS" origin I get another error: FeedError.CANNOT_SPECIFY_ADWORDS_ORIGIN_FOR_NON_SYSTEM_FEED
So my question is:
Is there a way to create or get the default "_Main ... feed" through the API when it wasn't already created by Adwords?

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