How to make the RL78/G1D Evaluation Board send data to smartphone APP through Custom Running Profile?

Recently, I have been studying the program of RL78/G1D Evaluation Board from renesas webside ( Bluetooth® Low Energy Protocol Stack RL78/G1D applications to communicate with RenesasBLE ), after connecting the RL78/G1D Evaluation Board with smartphone APP, the RL78/G1D Evaluation Board can receive data from smartphone through Custom Running Profile(in sample program demo_custom_run_profile.c--> DemoCustom_RunProfile_GattCallback-->RBLE_GATT_EVENT_WRITE_CMD_IND) successfully.

But when I tried making the RL78/G1D Evaluation Board send data to smartphone APP through Custom Running Profile, It did  not seem to work???

here is the program I added:

/************send data to smartphone***************/
RBLE_GATT_WRITE_CHAR_REQ Wr_Char;
Wr_Char.req_type = RBLE_GATT_WRITE_CHAR;
Wr_Char.charhdl = 1;
Wr_Char.conhdl = demoAppInternal.connectionHandle;
Wr_Char.val_len = 2;
Wr_Char.value[ 0 ] = ( uint8_t )(0x12);
Wr_Char.value[ 1 ] = ( uint8_t )(0x34);
/* API Call */
Ret_Status = RBLE_GATT_Write_Char_Request( &Wr_Char );
/***************************/

The write characteristic response event RBLE_GATT_EVENT_WRITE_CHAR_RESP is notified, but smartphone APP seems not receive any data.

Thanks!