Unable to get DTK in to recovery mode

Help somebody please.

I'm trying to get the DTK in to recovery mode as an update of one of the beta's bricked the machine.

I've followed all of the instructions (several times). The machine does not go in to recovery mode when holding the power button down whilst inserting the power cord.

The machine simply goes in to SOS mode (three flashing orange lights).

Anybody got any thoughts as I'm unable to use the hardware at all (and I've no help from Apple so far)

Thanks