Comment 12 for bug 580961

using 7-zip it can be solved!

eg:
wget http://www.ops.gr/Ergorama/fileUploads/ypiresiaops/prokirikseis/biografiko.zip
LANG=el_GR.CP737 7z x -oPATH file.zip
convmv -r --notest -f utf-8 -t CP737 PATH/*

see proposed patch for package unp, same problem there:
https://bugs.launchpad.net/ubuntu/+source/unp/+bug/583417