Pass page variable via ZML execute function

Pass page variable via ZML execute function

I am attempting to pass page variables through the parameters field of a zml element utilizing execute function, but it does not appear the page variable is getting parsed. Am I missing something?
  2. <pc padding='25px' hAlign='left' action='ExecuteFunction' functionName='loadContent' parameters='All_Insurances1,report,${Case_ID}'>
  3. <text size='4' value="Insurance"> </text>
  4. </pc>

When I inspect the loaded page this is what is shown:

  2. <div linkconfig= . . . "parameters":["All_Insurances1","report","${Case_ID"] . . .