aui_app populates the following INNOSETUP-related variables (if undefined):

CPACK_INNOSETUP_ICON_FILE = ${_ico} (installer icon)
CPACK_INNOSETUP_IGNORE_LICENSE_PAGE = ON (skips license page)
CPACK_INNOSETUP_IGNORE_README_PAGE = ON (skips README page)
CPACK_INNOSETUP_INSTALL_ROOT = "{localappdata}" (installs To AppData\Local)
CPACK_INNOSETUP_PROGRAM_MENU_FOLDER = "." (omits Start menu folder)
CPACK_INNOSETUP_RUN_EXECUTABLES = ${_executable} (runs the program after installation)
CPACK_INNOSETUP_SETUP_PrivilegesRequired = "lowest" (hence we're installing to user dir, we don't need UAC)
CPACK_INNOSETUP_SETUP_UninstallDisplayIcon = "{app}\\\\\\\\bin\\\\\\\\${_executable}.exe" (displays app icon in Control Panel/Settings)
CPACK_INNOSETUP_SETUP_WizardSmallImageFile = ${_ico} (small icon inside INNOSETUP window)
CPACK_PACKAGE_ICON = ${_ico} (app icon inside INNOSETUP window)
_aui_package_file_name = ${_aui_package_file_name}-setup (append -setup suffix for INNOSETUP)