Hello. My name is***** can help you with your question.
Because you have to press the center lock button to change the shutter speed, and then lock it back into place once the shutter speed is changed, the only way to change the shutter speed is with this style attached as it was originally. If it is not broken then the stem should still fit on the shutter speed mechanism in the groove. Your best bet for correcting this would be professional repair. There isn't really a workaround to setting the shutter speed without the snob in place.