Apologies. I didn't realize you had already posted in that thread, I stopped reading after Muliebuck supplied the answer.
So, you're trying to use this kuid in 12, correct? And it's a built in texture in 2010. Try this: Open 2010 and find the content, then open it for edit in explorer. Once it's open for edit, go up one level so that the folder for the content is the only item present in the open for edit window. Copy that folder and paste it on your desktop.
Close 2010 and then open 12. Once you have the content manager open in 12, choose the "import content" command, and browse to the folder you placed on your desktop, and import it. Commit it if you have to, and it should now be in 12.
I don't have any version installed right now, so I can't be more specific, or test it, but this should work.