RLS when connecting to an existing Semantic Model

Hello all,

I am currently developing a dashboard based on an already existing Semantic Model in my organization. Basically we are connnecting to the model and developing some alternative measures and visuals. We are trying to restric access to our new dashboard through some row level security rules based on users emails by connecting a table to the model and using UserprincipleName() to filter access but it doesn't seem to be working.

Do we need to define this rules in the original dataset? Is it not possible to define new RLS rules over and existing dataset? Is there a workaround? We are aware of this "Treatas" option (https://radacad.com/row-level-security-on-a-directquery-to-power-bi-dataset-composite-model-my-findings) but we would prefer not to use it as it would imply a lot of modifications in our measures.

Thanks in advance