How can one carry a bike with a step-through/mixte frame effectively?-- In comparison, any diamond-frame bike is a breeze for me to shoulder regardless of weight (okay, carrying a 25+-kg roadster is not exactly enjoyable, but it can be done): I've tried carrying a "true" step-through frame (but never a mixte) and it seems that, no matter how I hold the thing, I feel like an idiot and become exhausted after only a couple of minutes.
Online, I haven't been able to find much actual info on how to do it despite loads of discussion about how diamond-frames are so much easier to carry. On Lovely Bicycle!, however, there is an explanation of doing this for different models of step-through bike, but unless the girl pictured in that post is a deadlift champion, I don't see how it's possible to hold those bikes for very long.