I know it is like asking the poor Hummy to act like a computer, but is it ever likely that it will be possible to re-tune the channels whilst remote?
No, it is not worthy of a high place on the To-Do-List. However it would be helpful if view of the changes due in the next few months.The web-if does provide some diagnostic info regarding available muxes and strengths etc Scroll this page to the bottom but that is only if you can connect directly to the box from somewhere else (but this has been done with dynamic DNS and port forwarding wizardry Here (Click) .
The other option might be to see if the web-if could pass the diagnostic info out to the Remote Scheduling Portal? Although I couldn't say if that would be a popular requirement (how many times does your aerial need attention??) worthy of a high place on the To-Do list?