Hello.
I have problem with charset encoding in RSS...

I use ISO-8859-2 in "ACP/GYM SiteMaps & RSS/RSS/Charset" and
testing all methods in "Char-set conversion method".

I saw function called "iso_8859_2" in "recode_basic.php", it should work...

For testing, I use Windows, Apache 1.3.x and php 4.4.8.
Module cache is configured to: "[some_path_from_apache_conf]\mx_ggsitemaps\gs_cache/"
(cache is allways empty )

Is problem connected to Windows?

Well I'm not sure it is connected to windows, but it could. Usually, there is no need to chmod the cache dir with windows server, but make sure you can write in there, and as well, make sure that cache is activated.

Cache is activated...
But I tried both options.
I only wants to have correct charset encoding in rss...
Maybe should I write somewhere (hard code) 'ISO-8859-2' insted of 'UTF-8'?

Problem is, we do not dev on phpBB2 any more ... So I cannot easily tell you where the problem could be.
In the utf convector function, some char-set are aliases of other, it's possible that the char-set you want is not listed exactly as is in the list but that the mod is still about to deal with it.

Have you deactivate the mod since option ? Otherwise you could be tricked by your browser's cache, FF is more than advised to test this because IE seems to be more reluctant to fully clear it's cache.