Loading mrproject/planner documents with nautilus 2.6?

[Michael R Head <burner@suppressingfire.org>]

So I'm giving the experimental gnome 2.6 stuff a go (cool stuff!), and
I'm wondering how to make XML files that follow a specific DTD (and have
a specific file extension) be opened by a specific program.

The major example for me right now is .mrproject files, though it seems
like a general problem. Nautilus seems to be convinced that it's a
default text/xml document and wants to open it with Conglomerate,
despite the fact that planner has registered the .mrproject extension in
'File types and programs'.

Is there something I'm missing? 
Is there a way to override the discovered file type to get specialized
XML documents to be opened in specialized apps?

thanks,
mike

-- 
Michael R Head <burner@suppressingfire.org>
http://suppressingfire.org/~burner/