Shibboleth integration with ITunes U

Question

I have setup a shibboleth idp with the incommon federation. I am releasing the correct attributes to ITunes U shibboleth SP (as proven by the debug page at ITunes).
But, I am getting the following error:
"The format of the signature string is valid, but its value is not valid for the shared secret of the destination and for the received identity, credentials, and time."
The identity info does not contain any invalid characters, the credentials are normal and does not contain invalid characters, and the time is correct (idp is sync'ed by NTP).
Since I do not have access to ITunes U SP/transfer script, how do I know if the shared secret is configured properly on Apple's side?
Is it possible there is a shared secret mismatch between ITunes U and ITunes U SP/transfer script?
Here is the full debug page content (modified for privacy):
Received
Destination example.edu
Identity "I am abc_001" <[email protected]> ([email protected]) [urn:mace:incommon:example.edu!https://deimos.apple.com/incommon!2236eecf-24cc- 4f2c-a2c6-339e6bdd5695]
Credentials Student@urn:mace:example.edu:classes:fall2010:tc101
Time 1234884942
Signature 4b5922b5b1e46663243b0ad05d20dffbfee784707bdc3ba3c4934e24dee04a89
Analysis
The destination string is valid and the corresponding destination item was found.
The identity string is valid and provides the following information:
Display Name I am abc_001
Email Address [email protected]
Username [email protected]
User Identifier urn:mace:incommon:example.edu!https://deimos.apple.com/incommon!2236eecf-24cc-4 f2c-a2c6-339e6bdd5695
The credential string is valid and contains the following recognized credential:
Student@urn:mace:example.edu:classes:fall2010:tc101
The time string is valid and corresponds to 2009-02-17 15:35:42Z.
The format of the signature string is valid, but its value is not valid for the shared secret of the destination and for the received identity, credentials, and time.
To verify that your signature generation algorithm is correct, try using it with a shared secret of "SHARED-SECRET-FOR-ACCESS-TESTING" (hexadecimal value 0x5348415245442d5345435245542d464f522d4143434553532d54455354494e47). When you use that test shared secret, this debug page will indicate when you have successfully generated a valid signature for it. If you are seeing this paragraph, you have not yet generated such a signature.

Answer 1

I've been doing some testing and it seems like this freeze happens on Tabs that have a lot of videos. I've tested areas that are mainly audio and they don't seem to lock up iTunes.
Our site is ucf.edu
Two tab numbers you can try:
Lots of video: 2371361038.02398422861
Mostly audio/PDF: 2358190129.02358190137
Do you need the full link or can you get to them?