pc does't go to IRQ routine in lpc2148.

Hi...!!
I have one problem related to keil setting.
This is my code given below. which is working fine. which below keil setting.

keil > go in "flash" option > "config flash tool" > "Target" > tick "IROM1" (for start =0x0 to size =0x80000)

but when I do change in "IROM" (start = 0x2000 to size = 0x80000), At the time of interrupt, program is not generate any vector address table at 0x18,so I can't able to jump in to IRQ routine.

IS THIS ANY SETTING HAS TO BE DONE WHEN I WRITE 2000 IN IROM ??

#include <LPC214x.H>                     /* LPC21xx definitions   */
#include "Serial.h"

#define CR    0x0D

extern char ch;

void uart0_getkey (void)  __irq // This is the func which contr need to call when an interrupt occurs
{
  VICVectAddr=0x00;
  b=1;
  ch = U0RBR;
}


//---------------------------------------------------------------------------//
//------------------- Function for Initial UART0 ----------------------------//
//---------------------------------------------------------------------------//
void uart0_init()
{
  /* initialize the serial interface   */
  PINSEL0 = 0x00000005;           /* Enable RxD0 and TxD0                     */
  U0LCR = 0x83;                   /* 8 bits, no Parity, 1 Stop bit            */
  U0DLL = 0xc2;                     /* 9600 Baud Rate @ 30MHz VPB Clock         */
  U0LCR = 0x03;                   /* DLAB = 0                                 */

  VICIntSelect= 0x00;
  VICVectCntl0 = 0x20 | 6;
  VICVectAddr0 = (unsigned long)uart0_getkey;
  U0IER = 0x01;                   // enabled Receive interrupt
  VICIntEnable = 0x0040;
  temp = U0RBR;

}

//------------------------------------------------------------------------------------------------//
//---------------------------- Function for send character 1 time via UART0-----------------------//
//------------------------------------------------------------------------------------------------//

void uart0_putc(char c)
{
        while(!(U0LSR & 0x20)); // Wait until UART0 ready to send character
        U0THR = c;              // Send character
}

//-----------------------------------------------------------------------------//
//--------------- Function for send string via UART0---------------------------//
//-----------------------------------------------------------------------------//

void uart0_puts(char *p)
{
        while(*p) // Point to character
        {
                uart0_putc(*p++);  // Send character then point to next character
        }
}

My main file

*******************************************************************************************
#include <LPC214x.H>              /* LPC21xx definitions                      */
#include <stdio.h>                /* prototype declarations for I/O functions */
#include "Serial.h"





int b=0;
int temp;
char ch = '\0';
int main (void)
{




                                        /* execution starts here   */
 uart0_init();                                    // Initialize UART0




  while (1)
  {                          /* An embedded program does not stop */
           if(b)
           {
                uart0_putc(ch);
                b=0;
           }




  }
}

My serial.h file

#ifndef _serial_
#define _serial_


void uart0_getkey(void) __irq;
void uart0_init (void);
void uart0_putc (char);
void uart0_puts (char *);
void init(void);
extern int b;
extern int temp;

#endif