Subclassing non moose classes

Hi,

I'd like to subclass a non moose class Math::VectorReal so that I can do this

my $vec = new MyVector(x=>4, y=>3, z=>0);

and somehow fiddle with the arguments to effectively call:

my $vec = new Math::VectorReal(4, 3, 0);

I've been trying something like this:

package MyVector;

use Moose;
use MooseX::NonMoose;
use namespace::autoclean;

extends 'Math::VectorReal';

has [qw(x y z)] => (
    isa => 'Num',
    is => 'rw',
);

sub FOREIGNBUILDARGS {
    my $class = shift;

    my $n;
    my @values = grep { $n++ % 2 } @_;

    return @values;
}

But its not working, I guess because of the first caveat on the manual page that says that references must be the same between the moose class and the non-moose class.  I'm a bit lost to be honest, could someone point me in the right direction?

Thanks very much,

                                Matt.