That’s not partition 6, that’s filesystem type 6 which is the FAT32 DOS filesystem.
I don’t understand what you mean by ‘it must automount all to /fs/usb’.
If you say plug in 2 USB thumbdrives they can’t both be mounted as ‘fs/usb’ because you will then have duplicate names for the 2 filesystems (it would be the same as trying to have 2 C drives under Windows) and that’s illegal.
Or are you saying you want ‘any’ usb thumbdrive (QNX or DOS) to be mounted as /fs/usb AND you guarantee you are only ever having 1 drive inserted at a time?
In the second case if you look at the doc’s for io-blk.so you’ll see there is a + option available on the automount command for adding more drives/filesystems so you could do:
devb-umass cam pnp blk automount=+/dev/hd1t6:/fs/usb:dos,automount=+/dev/hd1t79:/fs/usb:qnx4
to automount either DOS or QNX filesystems to fs/usb.
Note: This still won’t solve multiple thumbdrives being inserted at the same time. Nor will it help you if a thumbdrive has multiple partitions on it because you’ll only mount the 1st one.
Note: Look at ‘Filesystems’ in the doc’s and you’ll see all the filesystem types. Likely you only want DOS (6 & 11) and QNX (77-79) so you can essentially get away with 5 automounts.