Works OK on 4.1.9 as well, just some minor changes in the standard code but you can easy follow the instructions and find where to place the code.
You can see an example at
http://www.shishapipe.net/shopcart/product.php?productid=16594&cat=296&page=1
This site uses menu tabs so I did not edit the
skin1/customer/main/product.tpl code, but instead entered this into the tab code for my site.
I followed my own instructions for 4.1.3 and found there where no code changes for 4.1.9 but just a few changes in the look for code, but you can easy find the area the code needs to be placed without problems.