Hi Oliver,
As per my suggestion, there are three ways to achieve this functionality.
1. Using multiple configurations and then writing logic in DO_CONFIG_DETERMINATION to determination Configuration at runtime based on attributes (in this case edit mode).
2. Using HTML coding as explained in the blog below.
3. This method is something I read sometime back on SCN itself by one of the legends of Web UI Andrei Vishnevsky - SCN Member of the Month May 2012 and then on checking the code I also think that this can be useful if given a shot.
The approach is to explore the method GET_CONFIG_DATA in view controller.
Thanks,
Ravi Katyal