APR::Request::Param charset and UTF-8 flag

Hi folks,

I'm not sure if this is a bug and I'm new to the list so please forgive 
any bad form.

I'm trying to use APR::Request::Param->charset(8) but it doesn't seem to 
be setting perl's UTF-8 flag as the documentation says it should.

Here's the code:

sub handler { my $r=shift;
    $query = Apache2::Request->new($r);
    $param_table = $query->param();
    $param_table->param_class( 'APR::Request::Param' );
    $_->charset(8) foreach values %$param_table;

    my $val = $param_table->{my_param};   # gives me a 
APR::Request::Param, OK so far
    print $val->charset();   # gives me '8', OK so far...
    print utf8::is_utf8( $val->value() ); # false!
    print utf8::is_utf8( $val ); # also false!
}

If this is correct behaviour then I can't see any purpose for the 
charset method - can someone enlighten me?

cheers
John