How to access External value from workflow in custom module

We have a workflow that gets called to set an external value (SetExternalValue activity) if the user declines the disclaimer.  I have a custom module for searching, in which I want to test the contents of the external value set in the workflow, to determine whether a particular layer can be searched or not.

 

I thought perhaps I could access it through the geocortex/framework/storage/Store by calling the 'get' method but using the key set in the workflow, the result always comes back as null.

Is there another way of accomplishing this or is this the right way and I'm missing some critical step?