They need to have purchased a service contract for each of their sensors to be updated.
(This is not enforced on CCO, but a service contract is legally required for downloading of the updates, and may be enforced in the future)
Then they need to be registered on CCO.com:
http://tools.cisco.com/RPF/register/register.do
(If they already have a CCO user account then they can use their existing account).
(Note: With the username you can manage the service contracts purchased:
http://www.cisco.com/cgi-bin/front.x/scccibdispatch?AppName=ContractAgent)
With the registered username they will be able to access the main download page for the IDS updates:
http://www.cisco.com/kobayashi/sw-center/ciscosecure/ids/crypto/
(Note: Accessing the files may also require additional agreements for Export of Encrpytion software)
