It BOOTS!
So I tried RMPrepUSB - not worth the effort. Lots of options and it probably does a lot. I tried it once and it didn't feel like it did what I was asking, so I gave up on it.
Back to SysLinux.
Unpacked all the files and folders onto my windows laptop.
Got a USB drive and made sure it was a single partition and formatted to FAT32.
Opened up an elevated command prompt and ran (my usb was on d)
syslinux.exe -m -a d:
All feels too easy as it just works and doesn't appear to do anything, but it does.
I then copied over the 2 buffalo files and the config you supplied (thank you)
It gets to the bootloader but complain that vesamenu is missing.
Go back to the unzipped files for SysLinux and in the BIOS directory search for vesamenu.c32 Copied to file it finds to teh root of the USB drive.
I tried again and this time it complained about another missing file. Find file in BIOS directory, boot again, another missing file, find file add to USB......
I ended up with a root directory of:
vesamenu.c32
initrd-atom_d510.buffalo
syslinux.cfg
vmlinuz-atom_d510.buffalo
libcom32.c32
libutil.c32
Put that into the NAS, power it on and it BOOTS!
I watch the attached monitor go through the menu and then start linux.
The usual scroll of text as things are loaded.
It paused and checked the speed of my disks.
It then paused and complained about no network... Ah yes, I need to plug the network cable in. but I am now back into familiar territory.
I'll go find network cables and free sockets to plug things into and go from there.
Thank you for all the help, I hope my ramblings about what I did to make it work from a windows perspective are helpful.
Chris