EDL is really a basic format. I suggest what the last post in that forum suggests: export a "speedgrade friendly" timeline with one video track and no transitions. You can export from speedgrade with handles and then reconform your original edit.
A bit esoteric? Yes, but really no more so than some of the workflows I've seen with DaVinci Resolve.
If you want a really integrated workflow, I would expect major improvements in the 6.5 release. Speedgrade is a recent acquisition for Adobe and their team did a huge amount of work before release to even get it in the suite.