ListGrid.exportData() has problems with nvarchar(max)

SmartClient Version: v10.0p_2015-02-18/PowerEdition Deployment (built 2015-02-18)

Browser is Chrome 44.0.2403.130 m

We built a button that uses ListGrid.exportData to enable the user to export data from the ListGrid GUI to an excel file.

This works mostly fine. But now I have a table in my MSSQL DB that uses nvarchar(max) for the description column of my table and I use the following datasource xml:

<DataSource ID="tempReport_isc_TimeTrackReport_0_645" serverType="sql" dataSourceVersion="1" dbName="CamCache" databaseName="CamCache" ispublic="true" schema="dbo" dbTable="tempReport_isc_TimeTrackReport_0_645" tableName="tempReport_isc_TimeTrackReport_0_645">
<fields>
…
<field name="Description" type="text" length="80000" title="Description”/>
</fields>
</DataSource>

When I load the table tha data is displayed correctly in the GUI. But when I export the data and open the excel file the description column, does not contain the displayed text but "java.io.BufferedReader@1846614b".
This also happens when I export to CSV.

When I change my DB to nvarchar(800) and the length in datasource to 800, everything works fine / is exported correctly.

So, what do I have to specify in my datasource xml that it exports the nvarchar(max) field correctly to excel?

Best Regards