Have you tried Googling it? The first link that I got when I searched for "aveo 06 towing wiring kit" I get this link to ebay item that found like what you're looking for. Plug and play. No splicing required.
Enjoy.
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0275854672

And it seems like you already found the right thread fort the people who already towed with an Aveo, but here's a link anyways viewtopic.php?f=41&t=27510