What's the status of Unicode/culture-sensitive operations in Ruby 1.9.1?

I tried following:

# encoding: UTF-8

str =3D "combining mark: a\u{30a}";
p str.index("\u{e5}")
# =3D> nil
# The result should be 16.

["a", "b", "c", "d", "e", "\u{e9}" "\u{e1}"].sort.each { |x| print x.dump, =
" " }
# =3D> "a" "b" "c" "d" "e" "\u{e1}" "\u{e9}"
# The correct result is:
# "a" "\u{e1}" "b" "c" "d" "e" "\u{e9}"


So it seems that string operations such as sort, index, etc. work on a bina=
ry representation of the strings (correct me please, if I am wrong), not ta=
king Unicode properties of the characters into consideration. Also does (wi=
ll) Ruby have notion of culture (used to collate etc.)?

Tomas