[mkgmap-dev] Precompiled sea tiles are w/o names - how to add the names?

Hi developers, I use the precompiled sea tiles http://osm2.pleiades.uni-wuppertal.de/sea/latest/sea.zip as mentioned on the mkgmap download site. Unfortunately they doesn't contain the sea names. How can I ad the names (at least in English, local languages would be nice) to my maps? Thanks for your ideas, Joern