display columns from 2 different tables in the same datagrid

Hello,

I need to display 2 tables in the same datagrid.
I've been playing with this http://support.microsoft.com/kb/319076/EN-US/
which works great except for a few things:
- I know no way to format the displayed data (I have some datetime columns)
- sorting does not work either
- I can't replace null values with what I want

I would like to avoid the hassle of merging my 2 datatables into a 3rd one
and then displaying it. Any changes in this datatable I will have to manually
update my 2 original datatables.

Eventually I have to implement this on a WinCE device so I'm also concerned
with performance issues.

This seems like a common issue (having IDs + data in one table and the
matching description + ID in another table and needing to display the
description + data itself) but I haven't found anything good but this MS
article.

Anyone has any ideas on how to achieve this?

Thanks,
Sitar.