What would be the preferred platform to build an application on top of AS
using writeback on some
measures. Writeback must be done on different levels.

This could be done just by having a dummy member at each level ... ?

What programming language c#, vb net ? Or doesn't that matter ?

/Michael V.

Doesn't matter which language. Use the DSO object model. It is
already there if you installed AS. If you want to install just the
component you should see it in your SQL SERVER install as a separate
component. You will have to InterOp if you use any of the .NET
language.