Your using a PPI which implies /usr/local/ is persistent.
However, it also means that you should use PPI compatible extensions.
keymaps.tce is not PPI compatible. It installs into /usr and not /usr/local/
Mixing PPI and non-PPI can quickly become confusing, you would have to add /usr/share/kmap to your /opt.filetool.lst and perform the backup/restore or setup and specify a tce directory to store and henceforth autoload keymaps.tce upon each boot.
Or perhaps, you can try to repackage keymaps to store in /usr/local and thus make it a PPI compatible extension, and many would benefit.