I'm pretty sure I have done this on my HP 7700p a long while back and I can't find anyone who says you wouldn't be able to do this. Can you give it a try and let us know how it goes? SOL just gives you a window to the boot screen (so it seems as if it shouldn't matter if it is updating the BIOs.) Also the firmware and BIOS are separate so since this is an AMT feature (ie, works via AMT) it seems like you should be able to do this.
Is there anyone else on this Forum who has tried this and could let us know if it was successful?
Could you give a little more detail on your success, please? Where did the ISO come from? Was it something you downloaded or created yourself? Did you use SoL simultaneously? If so, what did you observe on the SoL window? Thanks for providing any additional details.