Yes, that should work just fine. You can add that code to all your E-junkie thank-you pages by placing it in Seller Admin > Account Preferecnes > Common Thank-you Page HTML, or you can add it to the thank-you page only for purchases including a specific product by adding it in that product's own config screens where it says "Message (HTML) - Optional"



BTW, you may wish to consider the differences in behavior among the various payment processors when proceeding from Checkout to the thank-you page as described towards the top of this page:

http://www.e-junkie.com/ej/help.tracking.htm