sorry for the late reply and woow thanks for the response. Exactly what i've been looking for.
Actually, a little help with another rc-script and the 4th partition gets mounted, and the mkfs-tool shipped with the embedded img. So the embedded image deals very well with a classic 4-primary partition table. (and can mount FreeBSD (a5) and FAT (think 0c) partitions). Even DMA transfers seem to be supported by the alix-hardware (cranked up almost ~17MByte), though it will not run usb-disks too stable. :)
Oke, there's no partitioner tool inside then - maybe a good thing, agreed
And don't worry, just sometimes it's handy to have some extra space, like running a seldom-used-ftp or similar little abuses. Surely no caching with a lot of IO, this kind of storage is not made for this. (Though, the wrong thing to do here is to rely on this hardware and NOT having a spare card with a recent backup)
Yes I am aware that what i'm doing here is way beyond the purpose of pfSense, and i love it for as it can actually be done!
But I am aware as well, that it's the best non-commercial solution anyone can have, out of the box! (esp. soho environment where there's a lot of throw-away products!) :)
thanks a lot