LM3559: Turning On Torch Without TX1/TORCH/GPIO1 Pin

I want to turn on the torch mode of the LM3559 purely through register writes, and not using the TX1 pin.  It's not clear to me from the datasheet that this is possible.  What register configuration would do this?

Enable (0x10): 1a (Torch mode)

Torch Brightness (0xa0): 0x09 (56mA)

What else is required?

Thanks,

Chris