Retaining Wall Profile at Toposurfaces

It is widly recognized that Revit weakest link is the site grading and the new RAC 2012 still fall short in many of the site modification features, one of them is the ability snap to toposurfaces profiles.

The issue in discussion is as follows.  A pad is built over a toposurface, retaining walls are needed at the the pad perimeters, and the top of the wall shall follows the toposurface profile.  While a section view can reveal the actual surface profile, Revit cannot match it to the top of the wall. Simply said, one cannot snap to a toposurface profile in any sketch mode. This limitation has long been reported in wishlists for years.

Few workarounds exist. One approach, if your budget is generous enough, is to purchase EaglePoint's SiteWorks add-on, which enable this feature for several hundred dollars.  Another approach is to trace-eyeball the wall profile but we know this will not be accurate.  And my suggested approach is as follows:
1)  Create a section looking toward the wall and switch to a wireframe style.

2)  Export the section view as a dwg, using the default options.

3)  Link the CAD back into the section view, making sure it is positioned  "Auto - Origin to Origin" and placed in the "Current View only". The purpose of this is to use the ACAD linked lines as snapping references when modifying the wall profile.

 4) Edit the 'Wall Profile" and using the 'Pick Lines' tool, select the CAD profile lines. This is the accuracy we were looking for!

5) Erase the linked CAD dwg.

While exporting to dwg is a shotfall - the wall will not update should the surface changes-, the result is still precise. Share your thoughts if you have found an alternate method.