Customisation of the Thank you page

Dears,
I am using the last version of WP eCommerce and the last version of WP.

I would like to customise my thank you page, mainly in order to insert trackers for various advertising campaigns. How would you recommend to do that? What is the proper way without breaking the design of the plugin? (i.e. that do not need to be manually updated when a new version will be available)

Thanks in advance and keep up the good work!

https://www.ads-software.com/plugins/wp-e-commerce/