Is there a way to make the "Install and Restart" action async?

It takes about 1-2 minutes to finish installing the .pkg update to my application, and I'd like to allow the user to continue using it during the update. Right now, when the user clicks 'Install and Restart', the application "freezes" while the installer does its thing. After Installer.app exits, the user gets a quit confirmation dialog (from my app, not Sparkle). This seems to be by design since the app is waiting for the exit:

                          6209 -[NSApplication sendEvent:]
                            6209 -[NSWindow sendEvent:]
                              6209 -[NSControl mouseDown:]
                                6209 -[NSButtonCell trackMouse:inRect:ofView:untilMouseUp:]
                                  6209 -[NSCell trackMouse:inRect:ofView:untilMouseUp:]
                                    6209 -[NSControl sendAction:to:]
                                      6209 -[NSApplication sendAction:to:from:]
                                        6209 load_dsa_key
                                          6209 load_dsa_key
                                            6209 -[NSConcreteTask waitUntilExit]
                                              6209 CFRunLoopRunSpecific
                                                6209 mach_msg
                                                  6209 mach_msg_trap
                                                    6209 mach_msg_trap

Is there a switch to make this async, or should I file a bug report about that?

Thanks.