Problem modifying out-of-the-box TFS Report

[davidz]

My office has adopted Team Foundation Server to track and manage the
development and deployment process at our site. I have been asked to
modify one of the standard work item reports, "Related Work Items,"
that ships with TFS. I've successfully done some of these, which
involved changing the MDX code for the datasets that generate default
parameter values, but I am running into problems modifying the main
dataset, dsRelatedWorkIt ems. I am using VS2005. When I look at the
components of this dataset on the tree diagram for all datasets, all
of the correct fields are present, I can Preview the report and it
works. When looking at the Data page, I see the MDX query on top and
a results pane on the bottom. The results pane correctly lists all of
the fields I saw in the tree diagram across the top. But the query
itself does not look like the query that would have generated these
columns. Rather, the columns in the result pane correspond to the
rows in the query, not the columns. When I execute the query on the
data page, all of those columns disappear in the result pane, and the
only column that shows up is the single field that precedes the ON
COLUMNS statement in the MDX. At this point, if I attempt to preview
the report, it fails because it doesn't have the expected fields in
the dataset. If I try to switch to the design mode to see whether
there is any alternate definition of the dataset lurking somewhere, it
looks like all dataset definitions are lost. The properties page for
the dataset shows the fields correctly if I haven't yet executed the
query. If I try to make any of the modifications that I need to make
(which are simple -- I just need to remove some of the slicer
conditions in the WHERE clause), I am again unable to preview the
report.

It looks like the query that I see in the query pane is not what is
really being used for the dataset, and I'm stumped. I am not an
experienced MDX user, but I can do fairly basic modifications of the
type that are needed here. It seems like my problem isn't MDX syntax,
but rather how (or where) Reporting Services is keeping the query that
underlies this dataset.

Anybody out there have a clue that might get me back on track with
this? Thanks.