Retrieve the value from a parameter in a dax measure

Hello,

Let's say I have a simple table with 3 measures Total Amount, Total Quantity and Average Amount.

I have created a parameter ChooseMeasure with those 3 measures (from the modelisation menu).

I would like to create a measure in dax that multiplies the selected measure by 2 whatever the selected measure. 

I can display the name of the selected Measure with ChooseMeasure_SelectedMeasure= SELECTEDVALUE(ChooseMeasure[ChooseMeasure Champs])

But I can't find the way to get the value. I've tried the following but nothing is displayed

ChooseMeasure_SelecteValuex2 = 2*SelectedMeasure()

 Is there another simple way?

Example with a table where the measure is filtered on the filter pane to Total Amount:

The .pbi file is here 

Thanks a lot

Laurence