How to save blueprint macro local variable states ?

Hello,

I am currently working on the savegame of our game.
I would like to serialize the states of macros used in our level blueprints which are using local variables, such as DoOnce .
I flagged them as bPersistent, but i do not know how to access the corresponding UProperties (if they exist) to serialize them. Where do i find these local variables states from a LevelScriptActor instance so as to be able to serialize and deserialize them ?

Thanks,

François