Enumerate 'columns' in Entity Framework - vb.net

Question

we are dipping our toes with EF4 and have hit a wall.
We have an application that manages member data and a core requirement is to generate letters using Word mail merge.
In the current implementation we generate a dataset for the required records and enumerate it's columns and rows to create a tab delimited text file that Word can use to merge from. (This works really well, the Tab is used as there are multi-line results in the file such as FormattedAddressBlock).
With EF4 there is no way to convert internally to a dataset (this feature was dropped after the Orcas beta), so to the question:
How do we enumerate the columns and rows of a LINQ or ObjectQuery to allow us to build the text file.
Here is a sample of code we use with the datatable.
Using wmTextWriter As TextWriter = New StreamWriter(WordMergeDataFile)
' Write the header row to the merge data file.
Dim wmOutput As New StringBuilder()
For i As Integer = 0 To MergeData.Columns.Count - 1
wmOutput.Append(MergeData.Columns(i).ColumnName & vbTab)
Next
wmOutput.Remove(wmOutput.Length - 1, 1) ' Remove the trailing Tab character.
wmTextWriter.WriteLine(wmOutput.ToString)
' Loop through the datatable and write out the data rows to the work merge file.
wmOutput = New StringBuilder()
With MergeData
For iRowNo As Integer = 0 To .Rows.Count - 1
For iColNo As Integer = 0 To .Columns.Count - 1
wmOutput.Append(DOUBLEQUOTE & .Rows(iRowNo).Item(iColNo).ToString & DOUBLEQUOTE & vbTab)
Next
wmOutput.Remove(wmOutput.Length - 1, 1) ' Remove the trailing Tab character.
wmTextWriter.WriteLine(wmOutput.ToString)
wmOutput = New StringBuilder()
Next
End With
wmOutput = Nothing
wmTextWriter.Close()
End Using
Any help would be much appreciated.
Mark Harby
Nottingham. UK