how to run a task when external firewire hdd connects?

I need to create a Task which will autounlock an encrypted external hard-disk
when it is connected to Vista x64 Ultimate machine via Firewire interface.
Problem is, connecting Firewire HDD does not generate an event in EventLog,
so I have nothing to "subscribe" to in Tasks manager.

Is there any workaround for this?

Can I force Firewire HDD to create an event in EventLog when switched-on? Or
any other way around this?

(I cannot use autorun.ini as HDD is not readable due to encryption)