1. Download plugin from https://gist.github.com/loiane/909119
3. On the properties panel of your textfield click the "+" at the "Process Config" option.
4 Add the folowing code:
Note: as "plugins" is part of the configuration of the TextField and the Architech has no support for this or other configurations, this is the best way to access those properties.
config.plugins = [new Ux.InputTextMask('(999) 999-9999')];
I hope this helps someone out there.