Clean virtual terminal in Proteus

Hello 

I am new here, recently I working in Proteus using LPC2138 micro-controller
and make the programs in keil. 

I connect virtual terminal with LPC2138 and i able to transmit string to
virtual terminal, 

but i am not able to clean the virtual terminal.

Is any command in C program which clean the virtual terminal?

Here is code i c program:


#include <LPC213X.H>

#define in1 (1<<3)
#define in2 (1<<4)
#define in3 (1<<5)
#define in4 (1<<6)


void delay(unsigned int m)
{
  T0MR0 = 3000*m;
  T0MCR = 0x04;
  T0TC = 0x00;
  T0TCR = 0x01;
  while(T0TC < T0MR0);
  T0TC = 0x00;
}

void ser_tx(unsigned char ch)         // transmiter
{
  U0THR = ch;
  while((U0LSR & (1<<5)) == 0);
}
                      
char ser_rx()                // receiver
{
  unsigned char ch;
  while((U0LSR & (1<<0)) == 0);
  ch = U0RBR;
  return(ch);
}

void ser_str(char *ch)
{
  while(*ch != '\0')
  {
    ser_tx(*ch++);
  }
}

int main()
{
  //char buffer[100];
  char ch;
  IODIR0 = 0xff;
  U0LCR = 0x83;  //  Enable DLAB and using 8-bit character lengh
  PINSEL0 = 0x05;  // assign the PINs RX and TX for UART0  
  U0DLM = (unsigned int)((3000000/(16*9600))/256);   // calculate baud rate
for MSB
  U0DLL = (unsigned int)((3000000/(16*9600))%256);   // calculate baud rate
for LSB

  U0LCR = 0x03;  // Disable the DLAB, for protect the further changes to
these values
  U0FCR = 0x07;  // Enable and reset TX and RX FIFO

  ser_str("1. First Motor Rotate\r");
  ser_str("2. Second Motor Rotate\r");
  ser_str("3. Both Motors Anti-rotation\r");
  ser_str("4. Both Motors Stop\r");
  ser_str("Enter your choice for motor rotation\r");
  ser_str("Choice= ");
  while(1)
  {
    ch = ser_rx();
    ser_tx(ch);
    switch(ch)
    {
      case '1':
            IOSET0 = in1;
            IOCLR0 = in2;
          //  delay(250);          
            break;

      case '2':

            IOSET0 = in3;
            IOCLR0 = in4;
          //  delay(250);
            break;
      case '3':

            IOSET0 = in2;
            IOCLR0 = in1;
          //  delay(250);
            IOSET0 = in4;
            IOCLR0 = in3;
          //  delay(250);
            break;
      case '4':
        
            IOCLR0 = in2;
            IOCLR0 = in1;
          //  delay(250);
            IOCLR0 = in4;
            IOCLR0 = in3;
          //  delay(250);
            break;
      default:
            ser_str("\rSorry! Your choice is wrong\r");
            break;
    }

  }  
}