I did a quick search on this (I really need to learn more about it myself) and found this:
http://forum.isilo.com/showthread.php?t=144
iSilo documents may not need any special conversion, but do need a couple of converted Windows Cyrillic fonts (?), and cyrhack may also be useful (though perhaps out of date?):
http://www.enlight.ru/pilot/cyrhack/