So, the first link you posted relates to an “Inventory” activity, which doesn’t appear in the pre-configured SiWi account for mangOH. It took me a while, but I found this which clearly shows where the “Inventory” option is in the menu bar (on the left of “Monitor”). You can check in the screenshot I’ve uploaded that this option isn’t available.
I’m still trying the option in the second link you posted, but it doesn’t look good so far.
Anyway, I think I’m done trying to link the local MNO’s SIM to AirVantage. I’d probably go for other options.
Thanks for the help!