I just tried the approach from #104277, and it worked.
Apparently Time Machine doesn't care about the file system case sensitivity when copying Time Machine backups from a local USB disk to a networked Time Capsule disk. The only thing that matters, is having Time Machine first create the Sparse Bundle on the Time Capsule.
In other words, the instructions from #104277 can be followed, even in case the Time Machine backup originated from a case-sensitive file system.
I however can't rule out that it worked only because there were no case insensitive file/folder name collisions in the first place (e.g., no distinct files named 'file', 'File' and 'FILE' in the same origin folder).