Failed to commit national message to SVN

I try to commit some changes to SVN repository. When I enters russian commit message and push Commit button then svn fails with error about code 200 which cannot be connverted from/to UTF8. I try to change default editor encoding to System, but it do not help me.
It is possible, that commit message is passed to svn.exe in Local8Bit encoding instead of Utf8 (in the log: svn commit --encoding utf8 ...).