Domain mapping – with custom subdir

Hi, domain mapping works great, but I want to add a directory to the end of the path. Example:

Main wordpress install on:

Networked blog on:

Domain mapped to:

And now we want to have a custom subdir: with some files that will lead to some separate html files.

First I thought that it was as easy as adding a dir/files to the blogs.dir/2/ directory but it appears it isn’t. Any ideas/suggestions?