Simple customization of Sage 50 Accounting using Sage SDK

Will be able to do simple customization of Sage 50 Accounting using Sage SDK. Basically want to pop up a message when an even occurs, as an example let us when user of Sage 50 software submits a invoice want to pop up custom confirmation message box. Please let me know if this is doable to make Sage 50 Accounting to call into a 3rd party add-on which would pop up this message.

Thank You

- STR