If you are talking about Cartoon network on HotBird on 10949 V ,this channel can be opened with some receivers using seca 2 ID 0065 and op key of the month,cause this channel still use nano 5105.
Half of Cyfra+ channels are opened by some receivers like all Echolink/FTE MAX/SL 35S and others clones ,cause 0065 nano 5105 and 5108 are included in these firmwares.
Unfortunatly,I don't think your Humax have these nanos 5105 and 5108 included in firmware.