General Fitness & Nutrition: Calories burned hauling trailer

This week, I started hauling a trailer for the first time and I can't find any way to calculate calories burned. When I added the trips to my training log, it offered the standard entries but none included trailers whereas if you add a hike for example, the dropdowns offer a number of choices based on the size pack you're carrying. It would make sense, I suppose, that one's calories burned would differ if you're hauling 80 lbs in a trailer. Believe me, if my perceived effort was any indication, I burned a lot!

Any ideas? 

The one issue with changing your weight like that is that it will be reflected in your stats, throwing off your numbers if you are trying tracking that.  Can't you just type in hauling x# trailer?  It should then give you an "error" message saying that the workout can't be found at which time you should be able to add it and estimate the calories by selecting a similarly strenuous task.