IRQ Handlers in mdk 502 & mdk 473

Hi all.

I have MK70 based-board, and I need to use my own interrupt handlers.
MPU is configured and clocked correctly, all ports are powered and configured.
I'm trying to use SWI_IRQHandler() and override it in my main.c like a:

void SWI_IRQHandler(){
        osSignalSet( adc::Send, 0x0001);
        NVIC_ClearPendingIRQ(SWI_IRQn);
}

There is a breakpoint in this handler.
Enable and generate the interrupt:

        NVIC_ClearPendingIRQ(SWI_IRQn);
        NVIC_SetPriority(SWI_IRQn, 0);
        NVIC_EnableIRQ(SWI_IRQn);
        NVIC->STIR = SWI_IRQn;

When I debug the code after executing NVIC->STIR = SWI_IRQn command NOTHING happens.
When I press a Stop button in Keil, I see, that code's marker is at default irq handler at *_startup.s => Keil mdk 503 doesn't see my handler.

After that I've tried to detect a problem for a cup of days and still have no results.
But when I've tried to use mdk473 instead of mdk503, everything works fine.

Can anybody help me, please? :(