This can be done by adding a custom question (which you have mentioned already) and disabling the default question shown by InstallBuilder. This can be done by disabling
<askForConfirmationOnUninstall>- such as:
<project> <askForConfirmationOnUninstall>0</askForConfirmationOnUninstall> ... </project>
Thanks for your response. But I believe the best thing would be to change this from the en.lng file Installer.Uninstallation.ConfirmationQuestion=Do you want to uninstall %1$s and all of its modules? This should take care of it.