It's not particularly easy to work with Pronto hex codes and the Neo.

But there are options. Assuming the codes are learned (begin with 0000) then the only Neo-compatible editor that can directly use that format is RC3200 Setup. If you search the forums you can learn how to modify your NCF so that RC3200 Setup will load them, add your hex codes, then modify the file back for FreedomEdit.

Or, if you feel up to editing the XML file directly, you could try the Pronto2NEO Converter utility in the file area, which will convert hex codes to Neo format.

Finally, NeoHacker might work, but I don't know whether it supports FreedomEdit files.