Here is the firmware updater for the TSU-9300 with the ProntoScript flag turned on. Please note it is version 7.0.18.
Just to clarify, this is not a hack but just an edit of a config file that Pronto has in the "opt" partition of the remote's flash. The variable is called SF_SCRIPTING and I set it from 0 to 1. You can test this yourself with the simulator in it's data/product-TSU9300.conf file. The file has a clear comment above it indicating that it enables ProntoScript and it is used as an input to the Pronto GUI application that runs on the screen.