I'd like to have that guide too! it would be simply great to get rid of all exporting problems to autocad!
And, as a VW user, i can say i have the same problem with dxf or dwg files from Autocad. I guess the problem is that the 2 apps have a totally different way of organizing the drowing job. Based on my experience, i can say that the best way to export dxf or dwg file to autocad (if the files must be edited) is to create separate files for the exporting, delete all the presentation layers and simply enable the exporting classes as autocad layers. Doing that, i know that the autocad user will have separate layers that maintain my organization. The big problem comes with quotes: i usually create quotes on the presentation layers' viewports. In this case there is no way to have them back if u delete the presentation layers. But, if the file simply has to be used as a starting point in autocad, i dont see any reason to export quotes. Well.. if u are landscape architects (i envy u so much! ) ) u can ask to set the altimetric quotes in a specific class inside the design layers.
And.. that's all i can say about exporting to autocad... it's also a matter of luck: i the file will be opened by a totally brainless guy, everything can happen!
P:S.
I'm new in here and... i'm italian.. so, i hope u forgive my limited enlgish (i've learned it watching movies! lol). And i'm happy at the most for have found a forum of VW users: here there is nothing like that!