Characteristic tutorial : error when adding a characteristic to a service

I have a question concerning this tutorial : devzone.nordicsemi.com/.../ble-characteristics-a-beginners-tutorial

i have same problem than Milton (comment under the tutorial) : "I was able to add a custom service and verify it successfully on MCP. However, when I included the code to add a characteristic to the service, I always get "NRF_ERROR_INVALID_PARAM'."

he found a solution :

//for service
err_code = sd_ble_uuid_vs_add(&base_uuid, &m_base_uuid_type);
uuid.type   = m_base_uuid_type;
uuid.uuid   = BLE_UUID_OUR_SERVICE_UUID;

//For the characteristic:

char_uuid.uuid      = BLE_UUID_OUR_CHARACTERISTC_UUID;
char_uuid.type      = m_base_uuid_type;

i tryed his solution but i failed, i think it's because i do'nt know how to implement correctly the solution ...

(the tutorial work and advertise for me until this problem)