By putting mixers on them. Since 5.0 displays virtual channels, it now only displays channels with mixers, as the old behavior of displaying all channels makes the channel display page to unwieldy. So the model.ini in 2404 mode probably has 4 output channels and 2 or 3 virtual mixers in use. Default templates for all models only have 4 channels, so that's all you'll see.
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My remotely piloted vehicle ("drone") is a yacht.