Hello,
Which LV and NI-DAQ version are you using? That's always an important information when trying to help. What I suppose, without seeing your VI, is that the filtering option for the DAQ channel control is set to "Analog Input", which is the default value. This is (could be) the reason why you're seeing only the analog input virtual channels. So lets try this: Right click on the DAQ Channel control, select "I/O Name Filtering..." and then you can choose Digital Input or Output under the "I/O Type" control. You'll then see your digital channels.
Hope this helps.
Regards,
Luca
Regards,
Luca