Parsing form data to custom html on confirmation page

Dear unbounce community,

we are looking for a solution to parse field data to a confirmation page in unbounce:

1. We have an unbounce form with a field named “userid”
2. We added a tracking pixel on the unbounce confirmation page.
3. For each user the tracking pixel needs to get the “userid” parameter:
   <img src=“https://www.test.de/testimage_{{userid}}.png” width=“1" height=“1”/>

Does anybody have an idea how to manage this issue?