I did not find any directions for how to add the adwords conversion tracker in X-Cart 5. But I have learned just enough to pull it off and thought that I would share how I (And Google Tech support) did it.
Google adwords uses a tag added to the success screen to track if clicks they charged you for became sales.
I think they match this with the cookie that they gave the customer so they know what click became the sale. They show you this in the adwords admin area.
You will need the Custom skin Module installed and active in your store.
Go in via FTP and find the file
/httpdocs/skins/default/en/checkout/success_message.tpl
copy it to
/httpdocs/skins/custom_skin/default/en/checkout/success_message.tpl
The en directory is for English language and may be different for your store. You will probably need to create the checkout directory.
Edit the success_message.tpl in the custom_skin area to add your google tag to the end of it.
Mine looked like this:
<img height="1" width="1" style="border-style:none;" alt="" src="//www.googleadservices.com/pagead/conversion/999999999/?label=XXXXXXXXXX;guid=ON&script=0"/>
Go to your X-Cart admin area and re-deploy the store under the System Settings menu at the top.
The reason for doing this in the custom_skin is so that updates to X-Cart 5 don't overwrite it. If the success_message.tpl file gets updated for some reason that you care about, then you would need to redo this process.
BTW. This also lets Google track how many sales your making, and via big data analysis, who your customers are. So if you or your customers are privacy sensitive, don't do this.
Cheers,
Brian