Greek characters in Maxima



> Is there any Unicode TeX already ready and working

A Web search finds the following.  I have zero experience with either of
them, but you might want to look into them and report back to us what
you find out....

Omega and Lambda are Unicode versions of TeX and LaTeX (note annoying
use of case sensitivity :-) ) http://omega.cse.unsw.edu.au:8080/

There is "Unicode support for LaTeX" by Dominique Unruh
(dominique@unruh.de).  URL: http://www.unruh.de/DniQ/latex/unicode/
(there is a bug on this page which makes it not render correctly in
Internet Explorer -- you can go to the directory
http://www.unruh.de/DniQ/latex/unicode/content/ in that case).