htc touch上開發eMbedded Visual C++程式, 請問如何模擬function key

之前在用eMbedded Visual C++
開發for HP 4150 Pocket PC程式
現在想移植到touch

請問如何模擬出function key, 如
行事曆(keylist.vkC)、收件夾(keylist.vkA)、iTASK(keylist.vkB)
這三個鍵, 請問如何用接聽鍵、掛斷鍵取代

case WM_KEYDOWN:

if (wParam == (unsigned) gx_keylist.vkUp)
{ //UP
:
SendMessage(hWnd,WM_PAINT,0,0);
}

if (wParam == (unsigned) gx_keylist.vkDown)
{ //DOWN
:
SendMessage(hWnd,WM_PAINT,0,0);
}

if (wParam == (unsigned) gx_keylist.vkLeft)
{ //LEFT
:
SendMessage(hWnd,WM_PAINT,0,0);
}

if (wParam == (unsigned) gx_keylist.vkRight)
{ //RIGHT
:
SendMessage(hWnd,WM_PAINT,0,0);
}

if (wParam == (unsigned) gx_keylist.vkA)
{ //A 右二
:
SendMessage(hWnd,WM_PAINT,0,0);
}

if (wParam == (unsigned) gx_keylist.vkB)
{ //B 右一
:
SendMessage(hWnd,WM_PAINT,0,0);
}

if (wParam == (unsigned) gx_keylist.vkC)
{ //C 最左
:
SendMessage(hWnd,WM_DESTROY,0,0);
}

if (wParam == (unsigned) gx_keylist.vkStart)
{ //START 中間
:
SendMessage(hWnd,WM_PAINT,0,0);
}
break;