Hi Lish, in this case since you have all the curves for constructing that surface handy, I would draw some extension lines on those curves and then build a new surface from the extended curves.

Here you can see how I drew a line using tangent straight snap so that it comes tangent off of the existing curve:



I drew several of these, using distance constraint to make them all the same size (just type in 30 and push enter when picking the second point of the line):



Then I joined these curves all together, and made an additional copy of the top one higher up, then lofted through them to create a larger piece which can then be trimmed by your front outline:



I do want to add a surface extension mechanism in to MoI in the future, but for now you generally use this technique of extending curves and reconstructing the surface instead.

Another thing which may be handy here is after joining the curves together, you may want to go in and turn on points and delete the control points where the segments touch each other, that will fuse the segments into single larger segments which will create just one surface out of the loft instead of the 3 joined surfaces that I show here.

- Michael