Just to clarify, you can't watch the encrypted channels, just that the box will find them and show them in the channel list. Last I tried to scan with an RCA 800 box, the ION channel made the box very unhappy--it seemed to get stuck trying to figure out what to do with it.

On the topic of the DVB-S2 box though, here is the help for cusid:
help cusid
cusid
command cusid <oui> <swModel> <swVer>

And when I have the box print out the environment settings:
printenv
bootdelay=0
baudrate=115200
preboot=echo;echo Type "help" for more commands.
MS_BOARD=BD_MST124SZ.h
CUS_NAME=MST_7816_DEMO
logo_cmd=boot_logo 0 0 1 1
AppMagicFlagAddr=0x80000
info_exchange=spi
CUSTOMER_OUI=0x4D5354
AP_SW_MODEL=0x0001
AP_SW_VERSION=0x0001
HW_MODEL=0x0001
HW_VERSION=0x0001
OAD_NEED_UPGRADE=0
OAD_NEED_SCAN=0
USBUpdateFlag=0
usb_upgrade_port=0
usb_upgrade_path=usb_upgrade_all_flash.AP
filesize=2F87D8
usb_complete=1
usb_upgrade=0
bootcmd=spi_rdc 0x80b00000 0x8001c 0x2777b7; LzmaDec 0x80b00000 0x2777b7 0x80000
180 0x81000000; go 0x80000224;
LOGO_SPI_ADDR=70000
LOGO_BIN_SIZE=B054
panel_cmd=set_paneltype 11
stdin=serial
stdout=serial
stderr=serial

Environment size: 664/65532 bytes

So I'm guessing that the parameters for the cusid cmd for my box should have:
cusid 4D5354 1 1

And if you leave out the cusid line of the script for loading an upgrade that the box will take the upgrade regardless of the environment settings for it's "validity".