In total commander, tap the "\\" at the top it should show you registry, ftp and something else. Tap registry to go to the registry. That is why I did not include any other editors. It is a little limited, but as a basic editor it works alright.
Pocket Xpdf, psShutXP, and UPX4PPC installed, flashed and running. Anything else?
Oops, do not have the latest Null Keyboard and it is self registering. This might take a few minutes. Finally something of a challenge.