You create your devices first, then you create your activities. When you create your activities, the 810 copies the device page. If you make a change to your device after you create your activity, that change won't make it to the activity.

For example, if you create an HR20 device, an HR20 activity next, and then change the record button on the device, that change won't make it to the activity. You need to change the device before you setup your activity.