Override function parameters on before listeners

[caiocinel]

Is there currently any way to override parameters of the functions executed by the game when linked to a "before" listener?

Ext.Osiris.RegisterListener("HitpointsChanged", 2, "before", function(entity, percentage)    
    percentage = 100;        
end)

Doing this would set the points to 100%, but the original value of the parameter is still used when executing the function.