Why not call them?

Contact IBM
email: custserv@ca.ibm.com
phone: 877-999-7115

But as you may find as I did, not a model shows firewire on their website. Firewire incurs a license fee and to battle on price, it must go away. My firewire PCCARD was 20 bucks with a cable, so maybe this is what they expect you to do.