The value that you see for the label in the email that is sent is based on the name of the form element on the page, if you can you should try updating the name of the element with the value you would like to see for the label.
If this is not an option I can show you how to update this in the code itself if you post back with a copy of your webassist folder from your site and the page with the UE server behavior on it in a zip archive.