See http://forum.virtuemart.net/index.php?topic=123539.msg421677#msg421677 - the reference is for VM2 but maybe the same idea would work with VM3
Thanks to you! I found it. I created an override on the admin Template, I'm explaining this for others to use in the future.
As you told I took a look at the link you gave me, the steps was to create an override on the userfields view on the admin, means
Quoteadministrator/components/com_virtuemart/views/userfields/tmpl/default.php
after creating the override, I located the
$coreField = (in_array($row->name, $this->lists['coreFields']));
since the $coreField is used below line 88, I thought it's a good idea to make an empty string for it,
so you have to comment the $coreField, as you mentioned with " // " in the beginning of the line and add a new line with empty value
//$coreField = (in_array($row->name, $this->lists['coreFields']));
$coreField = '';
That's it, then you can have control over the default items.