Bingo!!! I did it, Herb. I'll explain to other people who might be as ignorant as me about the procedure.

Double-click on the source device (in this case Herb Crane's codes)
Double-click on the source page (in this case Herb Crane's Sony Amp STR-DB930)
Right-click on the source button (for instance power on)
Hit properties
Double-click Learnt (learned) IR Code
Copy the IR Code

Double-click on the destination device
Double-click on the destination page
Right-click on the destination button
Hit properties
Hit IR Code
Paste the IR Code
Hit OK

Download the new configuration to your Pronto and test the new button