Cannot override "product" layout in Joomla 4 override section

[Graph_1802]

Hi,
I'm using Joomla ‎4.2.8 ‎4.2.8 and Virtuemart 4.0.12.
Inside the override section of the template I'm trying to override virtuemart product layouts.
So I go to Create override -> com_virtuemart and click on "product".
The notice "Override created in /templates/shaper_helixultimate/html/com_virtuemart/product" appears.
BUT when I go inisde the override directory in FTP the product folder is empty.
The override of any other virtuemart layout works fine: this is the only one that doesn't work.
I have tried also on other domains and Joomla 4 installations: I always obtain the same result.
Can anyone help?
Thanks in advance!

[jenkinhill]

Please do not crosspost.
http://forum.virtuemart.net/index.php?topic=149669.msg534675#msg534675