How to read varibale from synch project variable set

Hello group!!

I have a Script property created in a Synch project mapping, and in the write script section of this propertie, I need the value of a variable defined in the Synch project variable set.

I have tried to access the variable like this -> $MyVariable$ but the compiler brings me up the error:

"The property (MyVariable) does not exist in schema type (Cloud user accounts (CSMUser))!"

Is there a way to achive this?

Kind regards,

David.