Hi Mark,
thanks for all your effort.
The use of the environment variable SAPLOGON_INI_FILE prevents the use of the ConfigFileOnServer-Key and any other server configuration within SAP GUI.
We need a kind of hidden reg-key to be able to set the path to a locally stored SapLogonTree.xml.
The main reason is that everyone uses the common saplogon.ini stored on the server, but the personal created favorites should be saved locally in his own SapLogonTree.xml.
Best regards,
Christian