Cannot run 64-bit OS in virtualbox-ose

["Slim Joe" <slimjoe2k8@gmail.com>]

Using virtualbox-ose 1.6.6-dfsg-2, I cannot run any x86_64
Linux distribution (e.g. Fedora 9). The guest OS complains
that I'm using an plain i586 machine. Is the open-source
version of virtualbox available in Debian at all capable
of running 64-bit guest operating systems? Note that I'm
using Debian AMD64 and can run x86_64 Linux and BSD distros
under KVM.

Host machine:
Linux localhost 2.6.26-1-amd64 #1 SMP Thu Oct 9 14:16:53 UTC 2008
x86_64 GNU/Linux

Modinfo for vboxdrv.ko:
version:        1.6.6_OSE (0x00080000)
license:        GPL
description:    VirtualBox Support Driver
author:         Sun Microsystems, Inc.
srcversion:     28947EB57F88449391DF966
vermagic:       2.6.26-1-amd64 SMP mod_unload modversions
parm:           force_async_tsc:force the asynchronous TSC mode (int)