VirtueMart 2.0.20.
For some reasons I needed to use template override in backend, but I noticed it wasn't working on Product Add/Edit view.
The fix is to remove line 57:
$this->addTemplatePath(JPATH_COMPONENT_ADMINISTRATOR.DS.'views'.DS.'product'.DS.'tmpl');
Which is not needed anyway to display the page.
If you remove or comment that line, you are able to create e.g. the file
/administrator/templates/[your admin template]/html/com_virtuemart/product/product_edit_price.php
and do whatever change you need to.
Hope this is useful to someone and that the fix will be included in future versions of VM.
Can this line be removed
It is still preventing overrides to the product edit template in Admin!
administrator\components\com_virtuemart\views\product\view.html.php
administrator\components\com_virtuemart\views\product\view.html.php
VmConfig::loadJLang('com_virtuemart_orders',TRUE);
VmConfig::loadJLang('com_virtuemart_shoppers',TRUE);
//this was in the controller for the edit tasks, I dont know if it is still needed,
//$this->addTemplatePath(JPATH_COMPONENT_ADMINISTRATOR.DS.'views'.DS.'product'.DS.'tmpl');