First create a virtual switch one for each mode as described here:
Then create a rest endpoint for each virtual switch as described here under app endpoint example
The virtual button should show up with the ability to create a rest endpoint. Select the virtual button and copy the url.
Take that url and setup a tasker task that sends an http get.
for the get the server port should be the beginning of the url https://graph.api.smartthings.com
And the path should be the rest Of the url.
Add some cool shield icons and then add a tasker widget and select the http get task.
This is about as easy as I can explain it without screenshots.