utf8 encoding problem with plperlu

The following short function illustrates a problem I'm having with the
plperlu module.

CREATE OR REPLACE FUNCTION
doublezero ()
RETURNS VOID
AS $$
use Encode qw/encode decode/;
$pass = "double00";
elog( INFO, "$pass" );
$mspass = encode( 'UTF-16LE', qq("$pass") );
elog( INFO, "$mspass" );
$$ LANGUAGE plperlu
STRICT;

# select * from doublezero();
INFO: double00
CONTEXT: PL/Perl function "doublezero"
ERROR: invalid byte sequence for encoding "UTF8": 0x00 at line 8, <DATA>
line 558.
CONTEXT: PL/Perl function "doublezero"

I don't understand this. I need to pass $mspass to Active Directory, and
it the encoding is exactly as it should be, which is to say, it works for
strings that don't include two consecutive zeros. Is this a bug?

-R-