DateTime not working with TT

I'm having a problem getting access to DateTime object functions inside a
template. 

The code looks like this:

test.pl:

--------------------

use Template;
use Template::Plugin::DateTime;
my $template = Template->new({
    INCLUDE_PATH =>
"/tmp",
    PLUGIN_BASE =>
'Plugin',
    COMPILE_DIR =>
'/tmp',
    DEFAULT =>
'404.html',
});

my $output;

$template->process('test.html',
$vars, \$output) or die $template->error();
print $output;

--------------------

test.html:

[% USE date = DateTime(today = 1) %]
Today is [% date.year %]/[% date.month %]/[% date.day %].
[% date.add(days => 32) %]
32 days from today is [% date.year %]/[% date.month %]/[% date.day
%]

--------------------

The result is:

undef error - Cannot compare a datetime
to a regular scalar at
/usr/local/lib/perl5/site_perl/5.6.1/mach/DateTime.pm line 
1255.

Basically, it looks like it's passing the time scalar instead of
the object (it's doing a compare of values instead of a call to the year
method. I can confirm this by looking at the input to the
DateTime::_compare function is, which shows as
"2004-10-14T00:00:00", the same thing I get if I create a new
DateTime object and do "print
$datetime_obj"

I've tried to get this working using the Template::Plugin::DateTime
module (used above) and by passing the DateTime obj as a var into the TT
- both attempts gave the same result. 

As I said, it appears that this is TT not knowing that I want to call
date as an obj not a hash or scalar (and the obj can be both).  OT:
oddly, so can Time::Piece and that works as expected.

Has anyone gotten this working?

Vitals:

FreeBSD: 4.10
Perl: v5.6.1
TT: Template-Toolkit-2.13
Template-Plugin-DateTime-0.01
DateTime-0.21

Thanks!