I don't believe my agreement with Cisco permits me to post it, but you could try reaching your local Cisco account manager to see if there's anything that can be done about getting the package directly from your local team.
The good news for you is that there is a section in the WLC config guide titled, "Assigning Login, Login Failure, and Logout Pages per WLAN." You can read it at this link:
Even without the downloadable bundle, you can create your own login.tar bundle by setting up WebAuth on your controller and then triggering the various conditions (login, login failure, logout) so that the pages display. Then you can just grab the page code, modify, and then re-upload as your own custom bundle.
NOTE: Do not use the WebAuth configuration "Preview" page as your baseline login page template. It's not the same as the actual login page presented at login time.
Transferring Crash file from standby: Login to the Active WLC in HA.
From CLI: (Cisco Controller) >transfer upload datatype crash (Cisco
Controller) >transfer upload filename (Cisco
Controller) >transfer upload mode tftp (Cisco Controller) >transfer
This is the start of a display filter cross reference between Wireshark
and OmniPeek. The 1st installment is a table of advanced filters. More
filters will be added as time allows. It is a living doc, so check back
for changes every so often Please feel f...