Great, thanks for your reply and help.
I was able to do what I wanted, I give you some code snippets to make several messages via a for loop,
I'm not a code proffesional but this works:

// Initialize messages
MyMessage msgInA(0,V_CURRENT);
MyMessage msgWhA(0,V_WATT);


#define NSENSORS              6				//used current sensors

void setup()
{  
	//initialize energy monitor CurrentSensor
	for (int i=0; i<NSENSORS; i++)
	{   
		wh[i]        = { 0.0 };  //initialize wh
		lwhtime[i]   = {0};	//initialize time
		present(i, S_MULTIMETER);  
	}  
	for (int i=0; i<NSENSORS; i++)
	{  
		present(i, S_POWER);
	}
}


	
void loop()
{
  	for (int i=0; i<NSENSORS; i++)
	{
		send(msgInA.setSensor(i).set(Irms[i], 1));
		send(msgWhA.setSensor(i).set(wh[i], 1));    
	}
}

Thanks