CPDLC Position Reporting

[DeltaXrayWhiskey]

Hi. Should I be able to send position reports via CPDLC via the ATC COM Menu under "POSITION/REPORT" page. I am currently doing a flight across the Indian Ocean and Brisbane Radio advised that I should do CPDLC position reports and they thought I should be able to but that does not seem to be the case. I know ADS-C reporting works but in this case Brisbane Radio are not able to receive those reports. Is this supposed to be a feature of the A350 or does that page just help with voice based position reports?