You may want to post Pronto related questions in the Pronto forums in future, but here is a quick summary of what is required.
In ProntoEdit, Add a new device. Expand the device, right click on it and create a new panel. On the new panel, Add a new button. Double click this new button and click on the 'Set IR' button on the Action tab. This will open a new dialog box. Click on the 'View IR >>' button. The HEX codes need to be pasted in the text box that appears. Save the config as a .CCF. In the URC software, open this using the Universal browser, select the button and drag the "Learned Data" from the "Action List" to your button.
Hope this helps