Manually enter time in HR zone

I can't upload my HR data (I have a polar HRM) so I can't track my time in each HR zone.  Is it possible to manually enter this information?  If not would it be possible to add this feature?  I've heard rumors that you're trying to support uploads from additional HRM but I understand it isn't a trivial process to do so.  Allowing people to manually enter time spent in each zone as part of a workout would be very useful and would help fill the gap until other HRMs are supported.

Thanks,