How to turn the connection string of a custom connection manager to sensitive?

Hi All!

We built a custom connection manager for SSIS, that uses the ConnectionString property to store the connection details.
When I try to assign a sensitive parameter to the connection string, SSIS refuses to do so, because "sensitive parameters can only be used with sensitive properties".

How can I turn a regular connection string to a sensitive property. Do I have to apply some kind of attribute in our code to mark our connection string as "sensitive"?

Thank you all in advance for the help!

Cheers,

Patrick