IIRC, orinoco_cs uses iwconfig to set the wireless params,
manually you can type commands like:
iwconfig eth0 key 0123-4567-89ab-cdef-fedc-ba98-76
iwconfig eth0 key s:WePkeY
the relevant section from man iwconfig is:
Used to manipulate encryption or scrambling keys and encryption mode.
To set the current encryption key, just enter the key in hex digits as
XXXX-XXXX-XXXX-XXXX or XXXXXXXX. To set a key other than the current
key, prepend or append [index] to the key itself (this won't change
which is the active key). You can also enter the key as an ASCII string
by using the s: prefix. Passphrase is currently not supported.
To change which key is the current active key, just enter [index] (with-
out entering any key value).
off and on disable and reenable encryption, open set the system in open
mode (accept non-encrypted packets) and restricted discard non-encrypted
If you need to set multiple keys, or set a key and change the active
key, you need to use multiple key directives. Arguments can be put in
any order, the last one will take precendence.
iwconfig eth0 key 0123-4567-89
iwconfig eth0 key s
iwconfig eth0 key  open
iwconfig eth0 key off
iwconfig eth0 key restricted  0123456789
iwconfig eth0 key 01-23 key 45-67  key 
and it should be fine to set these in the /etc/pcmcia/wireless.opts file.