DBD::ODBC does not support bind_param_inout?

Hi,
I have installed the DBD::ODBC from the latest svn.

when I want execute a procedure like this:

________
my $whoami = "";
my $csr = $dbh->prepare(q{
BEGIN
:whoami := PLSQL_EXAMPLE_DARREN.FUNC_NP;
END;
});
$csr->bind_param_inout(":whoami", \$whoami, 20);
$csr->execute;
print "Your database user name is $whoami\n";
$dbh->disconnect;
----------

but I failed with:

____________
/usr/bin/perl -w /home/darren/perl/dbitest.pl
Can't bind unknown placeholder ':whoami' at /home/darren/perl/dbitest.pl
line 90.
-------------

I have both used $dbh->{odbc_ignore_named_placeholders} = 1 and
$dbh->{odbc_ignore_named_placeholders} = 1

Any suggestions?
.