Hi,

I would go into using Fiddler to listen to the network events once you click the button originally on the form, and then try to simulate it the way you want.

However - reject/approve is just a matter of setting different value for the dropdown field. The Nintexbuttons, once clicked, before make POST request, are setting dynamically the crucial values on the form.

I guess you can use REST API to update task item when user clicks on form your custom buttons. I see quite much effort to do that however

Regards,

Tomasz

have a look on this