This is not true.
I currently use CXF 2.6.10 and I had to use the version 2.2.5 of JAXB. I tried with the version 2.2 (copy/paste from the documentation page) and I still had the original problem about "unmappable charset". The documentation page also indicates to use the latest version of JAXB (as of today, 2.2.11). I did and got some other issue about missing classes.
CXF-2450 explicitly mentions 2.2.5. I tried with that version and finally it succeeded.
Therefore I believe the documentation is inaccurate must be adapted to reflect this.