How do I create a data field on an Edge 1040?

On my Edge 1000 I was able to create a data field with this calculation: totalascent / distance.  I called the data field VFM (Vertical Feet gained per Mile).  I can't figure out how to do it on an Edge 1040.  It looks like Waldenmeier developed a similar data field but it works in meters.  I want it to be general so that it will use US settings and not metric settings.  Thank you.