ke_timer_set not execute,why?

I have a problem ,ke_time is not succeed execute everytime.

in detail:
In SDK 3.0.6,I used a button P23 to power on the system.

void app_button_enable(void)
{
wkupct_register_callback(app_button_press_cb);

//if (!(GPIO_GetPinStatus( GPIO_BUTTON_PORT, GPIO_BUTTON_PIN )) ) //button is p23
wkupct_enable_irq(0x80000, 0, 1, 10); // P2_3, polarity low , 1 0x40000
}

in app_button_press_cb(void)
I add this:

havekey_flag =1;

if(keytimescn>=1)
{
keytimescn =0;
ke_timer_clear(SCAN_KEY_TIMER,TASK_APP);
}

keytimescn++;

if(PW_ON_OFF!=0) //power off statue to power on
{
//ke_timer_init();

GPIO_SetInactive(GPIO_TI_LED_PORT,GPIO_TI_LED_PIN); //fot tip enter here the led is on

ke_timer_set(SOTF_PW_TIMER,TASK_APP,200); //only here call SOTF_PW_TIMER's function
// app_force_active_mode();
}
else
{ //search for 400MS_key
GPIO_SetInactive ( GPIO_ALERT_LED_PORT, GPIO_ALERT_LED_PIN); //fot tip enter here the led is on
button_type =BUTTONTYPE_400MS;
ke_timer_set(SCAN_KEY_TIMER,TASK_APP,40);
// app_force_active_mode();
}

here I haved add MSG
enum APP_MSG
{
APP_MODULE_INIT_CMP_EVT = KE_FIRST_MSG(TASK_APP),

SOTF_PW_TIMER,
............
............
}

/* Default State handlers definition. */
EXTERN const struct ke_msg_handler app_default_state[] =
{
{SOTF_PW_TIMER, (ke_msg_func_t)poweron_soft_handler},
{GAPM_DEVICE_READY_IND, (ke_msg_func_t)gapm_device_ready_ind_handler},
.............
...........
}

In handler function:

int poweron_soft_handler(ke_msg_id_t const msgid,
void const *param,
ke_task_id_t const dest_id,
ke_task_id_t const src_id)
{
GPIO_SetInactive( GPIO_ALERT_LED_PORT, GPIO_ALERT_LED_PIN); //fot tip enter here. the led is on

{//soft poweron is the first prio
PW_ON_OFF =0;
been_tip_flag =0;

app_adv_start();

led_been_loop =TIP_LOOP_LEDON;
ke_timer_set(LEN_BEEN_TIP_TIMER,TASK_APP,1);
}

ke_timer_clear(SOTF_PW_TIMER,TASK_APP);

return (KE_MSG_CONSUMED);
}

I press key P23 to high one time last 6s { greater than in set here (ke_timer_set(SOTF_PW_TIMER,TASK_APP,200) 2s};
have enter the step:
GPIO_SetInactive(GPIO_TI_LED_PORT,GPIO_TI_LED_PIN); //fot tip enter here the led is on

但有时the step is not in:
GPIO_SetInactive( GPIO_ALERT_LED_PORT, GPIO_ALERT_LED_PIN); //fot tip enter here. the led is on

so the system is not poweron everytime.

my question is :
ke_timer_set(SOTF_PW_TIMER,TASK_APP,200); //only here call SOTF_PW_TIMER's function

但有时this function
poweron_soft_handler

is not call succeed.

why?

additional:
I have view this
http://support.dialog-semiconductor.com/faq/how-use-ketimer-during-wakeu...

but in 3.0.6 have no this MSG

struct create_new_timer_struct *req = KE_MSG_ALLOC(APP_CREATE_NEW_TIMER, TASK_APP, TASK_APP,

create_new_timer_struct);

create_new_timer_struct
and
APP_CREATE_NEW_TIMER
not included in my used SDK(3.0.6).