I tried the test file in Fedora + RPM-packaged OOo 1.1, and the results are the same as with RH9, except that the line with the Open Symbol greek letters does show up both in OOo and an exported PDF file.
I noticed that inserting Greek characters in 'Standard Symbols L', 'Open Symbol' or 'Symbol' using 'Insert->Special Character' now seems to work for some reason in Fedora (it didn't before). Standard Symbols is still invisible in the drop-down font list in the tool bar. If I click on the empty line, then the selected font reads 'Standard Symbols', but typing anything inserts only invisible characters into the text. Directly typing in 'Open Symbol' inserts empty rectangles.
I use a Finnish keyboard layout, but the language locale is set to en_US.UTF-8. I also tried with the locale set to plain en_US, but running 'oowriter' from a terminal with that setting gives a few Perl complaints about being unable to set the locale and falling back to 'C'.
Mikko