I have found the problem:
It's the namespace!
After removing the namespace, all of the comments were shown.
Seems like VS2008 has problems with interpreting intellisense XML comments of different namespaces.
Can anyone confirm that?
And is there a solution for this problem?
(BTW: Which id*** downvoted my question? Is it really so useless?)
Edit:
It's now working correctly.
I have found the final solution: Install SP1 and a couple of hotfixes for SP1!
- VS2008SP1DEUx1512964.iso
- VS90SP1-KB957507-v2-DEU-x86.exe
- VS90SP1-KB957912-x86.exe
- VS90SP1-KB958017-x86.exe
- VS90SP1-KB960075-v2-x86.exe
- VS90SP1-KB963035-x86.exe
- VS90SP1-KB967631-x86.exe
- VS90SP1-KB971932-x86.exe
- VS90SP1-KB976656-x86.exe
- VS90SP1-KB2498381-x86.exe
hotfix descriptions can be found on the MSDN website.