interupt in Keil uVision3

Hi.
On the first I want apologize for me stupide question.
To day I sownload KEIL and install .
ther I can simulate all what I want.
but now have problem to handle interupt.
LPC2142
If use example to generate interupt with timer0 - generate interupt only
once.
(debuging in PC -simulate). and if match register generate interupt (bit
is set ) but no jup to handle interupt again.On VIC is set RawInt.
IF download code do MCU work good .

regards