JEuclid has native support for reading files created with OpenOffice. All JEuclid apps can open and work with .odf files directly.
OpenOffice up to 2.0.x used the "OpenSymbol" font with characters in the private Unicode range. A mapping table exists, and all characters should be mapped. If you encounter a non-working character, you may be missing a font (see file a usage). If that does not help, please file a bug report. Do not forget to attach the .odf file!
OpenOffice ≥ 2.2 uses the standard Unicode character range. If you encounter a non-working character, please install a Unicode font). The OpenSymbol font should work just fine, as long as its from OO ≥ 2.2