This describes how to not only get iTunes Match working with iOS 6, but how to get back all the allocated memory, that you will probably lost.
Let's use MOBILedit universal all phones manager, available at www.mobiledit.com. Although it is not free, authors provided for this occasion a special code, which provides full license for one phone to end of October.
Visit this address: www.mobiledit.com/vip
Enter the Code: IPHN-1210-3BA6-1B37
And after the basic registration you will get the activation key.
Watch this video, to see steps below http://youtu.be/egiHNx_Zy28
1. Delete these files:
iTunes_Control\iTunes\MediaLibrary.sqllitedb
iTunes_Control\iTunes\MediaLibrary.sqllitedb-shm
iTunes_Control\iTunes\MediaLibrary.sqllitedb-wal
2. Restart your phone.
After this operation all my music plays, but online from iCloud, phone can't see 25GB of music stored in the phone memory. It is important to get the memory back. I achieved it in this way:
1. Download a few songs from iCloud (don't forget to turn on iTunes Match)
2. Go to Settings->General->Usage
Now you will see the application Music in the list with just those few megabytes of downloaded music.
3. Tap on the Music icon, Edit and Delete all the music.
Now you should have your phone memory available. If the memory isn't released yet then:
1.Turn off iTunes Match.
2.Restart your phone.
3.Turn on iTunes Match.