AutoCAD Civil 3D :: Footways With Offset Assembly?

I designed a very straight forward piece of road consisting of a centreline, 2 channels and a footway either side. I played around with superelevation, assemblies and created a corridor. This all works fine.

Now when I add a taper to my offset alignments (for instance to widen the carriageway at a junction approach in order to add a splitter island), I noticed that the corridor stays perpendicular to the centreline. So this means the 2m wide footway I specified is not actually 2m wide, measured perpendicular from the curb. (See attached)

I have figured out that I can achieve this by attaching an offset assembly to the curb and attach the footway sub-assembly to the offset assembly. (So the curb acts a bit like a subsidiary string in MX). However, in order to make this work, I need to assign the horizontal alignment and Profile of the offset alignment to the Offset in the Corridor Properties Parameters (see attached). So far I have only managed to do this by creating a temporary surface which is wider than the curbs, so I can apply a profile to the offset alignment.

This seems a bit of a silly work around for such a standard simple highway design principle. Is there an easier way to create footways that are not perpendicular to the centreline?
 
Why is the superelevation I have assigned to the centreline, not projected onto the offset alignments? If this was the case, the offset alignments would have had a profile automatically?If you attach the offset assembly to the curb, why does it not automatically know it should stay attached to the curb? ie, remove the need to specify te horizontal alignment in Corridor Parameters?Is there a curb subassembly in existance that will project anything attached to it, perpendicular?

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