osmo-nitb enable SMS delivery reports

Hi, I'm using osmo-nitb in a testing environment and I've soon received a request to enable SMS delivery reports. After looking on the user manual, I couldn't find anything related to this. I've also enabled debug logging and tried to grep for something like that when sending a SMS between two handsets that have SMS delivery reports enabled, without finding out anything. (SMS delivery reports tested and worked on a public telephony system, for those two handsets) Is there such an option available in osmo-nitb to enable delivery reports? --- Thank you, Stefan