It seems that Dutch localization was added in version 12.5 (How to localize FBReader interface for your preferred language
). I don't know if fbreader180 is based on the 12 series, but if it is you should be able to add the "-nl.xml" files. However, as you discovered, this does not give you hyphenation.
Is the hyphenation for German "good enough"? That might be a work around for the Desktop version (manually select German under the book info icon).
I suggest posting a question on FBReader Google Group
about Dutch hyphenation. You can include the Dutch newspaper as an example. If German hyphenation looks good (or better than nothing) you can mention this, because using German hyphenation for Dutch is probably an easy fix to make.