Redmine

Hello there. We have bitnami redmine with SVN. Tables in utf8. Source codes in ANSii utf8 , at command performance diff or if simply to look at a source code, a problem with comments in a code. Some codes is non UTF8 and some txt files in cp2151.If comments in Russian they aren't displayed or go small squares or... How with it to struggle?
In attachment part of c# file (VS 2005) with Russian comments.