Please try IrScrutinizer
. You need some supported hardware, presently supported are IrWidget, GlobalCache (with IR receiver), IrToy, the CommandFusion learner, and my own favorite toy
(if you can build things), and Lirc (with some restrictions).
The program is being actively developed, so feedback, e.g. improvement suggestions, is welcome.
For submitting to Logitech, you can probably do an export in "text" format, containing Pronto Hex.