Mercedes-Benz BLUETOOTH PHONE INTEGRATION ECP/M MERCEDES - Manual (Page 9)

Unused features
Your radio was not designed for Bluetooth operation, but rather
for a hardwired phone module.
Tooki emulates many of the functions supported by the radio.
However, certain functions are designed to work only with the factory
phone and can not be used by Tooki. Therefore, you would
notice some unused menu items.
List of unused menu items:
Store - All changed are void at restart
Hold Call - Works with some phones
New Call - Works with some phones
Add - All changed are void at restart
Edit - All changed are void at restart
Delete - All changed are void at restart
SMS - Works with some phones
Forward Call - NOT AVAILABLE
PIN Setting - NOT AVAILABLE
Phone Setting - NOT AVAILABLE