Modifying doorbell to register a SmartThings device connection?

I'm hoping someone can help me here.

I've got a Byron BY601 Wireless doorbell which comes in 2 parts - the chime and the doorbell.
The Chime takes 3x AA batteries, and the doorbell takes 1X CR2032 battery.

What I'm trying to do, if figure out a way that when the doorbell is pressed, it activates the connection on a SmartThings device.

I have a SmartThings multiswitch which can acts as a Reed Switch for an Open/Closed signal to SmartThings, this however, takes a  CR2450 battery.

I've attached some images, but I'm wondering if anyone reckons they might be able to figure out just by looking where I could make some connections to trigger the device to activate?

Picture of Modifying doorbell to register a SmartThings device connection?

I can't really follow you, but I try anyway...
1. Why not check if the switch on the remote just connects the battery to the circuit?
If so you can power your Smart Thing from the same connection - 3V is 3V.
2. Even if there would be an easy connection inside the doorbell - it would only stay active till the sound starts, so basically same like 1.
3. You can use the signal to the speaker to trigger a signal.
Only if there is sound the speaker get's supply, so a transistor can be substituted to give you an "on" signal.
Of course some additional electronics are required.