case sensitive identifiers in 7.3.4

The documentation clearly states in section "1.1.1 Identifiers and
Keywords" that "Identifier and key word names are case insensitive".
It goes on to give an example where a column name is used in lower case
and in upper case or any mixture.

I have found that the actual implemented behavior is not
in conformance with the above. It can be demonstrated in psql
if you create a column whose name is mixed case , e.g. "DocRoot" in table
"websites" that
    select "DocRoot" from "websites";
works and that
    select "docroot" from "websites" does not.
This isn't specific to psql. I found it when using the Class::DBI Perl
library (built on Ima::DBI, DBI, and DBD::Pg ). Somewhere between my code
and the database the column name was forced to lowercase and therefore the
query faild. As noted I reproduce this behavior with psql.

this is on SuSE 9.0 with postgresql 7.3.4-53