HP3585A GPIB command set?

Does anyone know where I can find a list of the GPIB commands for the HP3585A spectrum analyzer?

I know the command set is different from that of the 3585B. I've just aquired one of these and would love to be able to plot to a file on my pc. (I have a GPIB interface card type PCI-GPIB-300K from Measurement Computing + the drivers for the card)

I guess there's no low-cost software around for this purpose, the most cost-effective I've seen is from 'Aphena' here in the UK.

Chris Morriss.