i am really soooo thankful for your help/support.
with your help i found the file now.. no change..
i will try it one more time - and then i leave it where it is now
i enclosed you the original default.php (from com_virtuemart) and the default.php (in template file, so thats the override).
in the override i have no idea where to add the changes, with the original i did add it right under:
echo shopFunctionsF::renderVmSubLayout('addtocart',array('product'=>$this->product));
in line 157 with no visible changes, so i reversed.
guess... I am ok with it as it is, right?