Actually, no license key is needed with the full version of the component. So just log into your account, download the full licensed version of your Rebex component, install at the developer’s machine, and then remove the references to the old trial version in your Visual Studio project and add references to the full version of the component binaries. (If you were setting the trial key previously, just discard this line).
For more info check the knowledge base article about updating to full version or
see this forum question on how to upgrade from trial to full version.