Magento 1.8 add to url via url query

Would like to add a product via an url like (as described in this Mage article):

echo "

This doesn’t work in Magento 1.8 unfortunately, because of the new form_key system. You can provide an hidden form_key field. Unfortunately this didn’t work in my case. Best way is to omit the form_key security for add to cart querystrings. This can be solved with this rewrite plugin:

https://github.com/deivisonarthur/Inovarti_FixAddToCartMage18/

Good luck!