Well, your only chance of controlling an RF device is if the Pronto and device in question are on the same RF frequency.

If they are, you then need to get an RF-to-IR converter (the receiver half of a standard RF-based IR extender system) that also operates on the same frequency. Send the RF command from the original remote, and the RF receiver/IR sender should spit out the resulting command as infrared. Learn that into your Pronto, and if you configure that device in ProntoEdit to then work as RF, theoretically it should control the lamp.

In case you were wonding, universal remotes with RF are *not* designed to controll RF devices, they are only designed to control IR devices using an RF basestation matched to the remote.