Network homes win2012server no write access to keychain

We are using win 2012 R2 server for our network based home directories (smb). The home folders are stored and used directly on the server.

Although the user for example "eric" has all permissions on his complete homefolde on the server inclusive ~/Library/keychains/login.keychain, no entries are stored. When adding an entry manually in the keychain "login" the following message appears: An error has occured. Unable to add an item to the current keychain. Unix[Permission denied]".

Keychain is open, Keychain first aid does not work. Creating a new keychain or deleting the keychain-file does not help. The system creates temporary keychain-files like "login.keychain.sb-cafdf3aa-ceg1c".

We are not sure, if the following belongs to the same problem:

When creating a file with text edit, the system also creates 2 files for example "test.rtf" and "test.rtf.sb-cafdf3aa-tk8f3m" when changing the file and storing again.

Help is highly appreciated :-)