No parameters for the control and estimation tools manager

We want to use the control and estimation tools manager in simulink to estimate parameters in our model, but get into problems when adding variables for the estimation task. The parameters we have a added aren't known for the control and estimation tools manager.

As we understand it, to get parameters here, simulink needs to know that these variables exist, so these need to be added in the model explorer. This is done by selecting the Model workspace of the simulink model then go to add in the toolbar and selecting Simulink Parameter (shortcut ctrl+P). But this doesn't work. Are we doing something wrong? Are there more preconditions for these parameters to work?