DisplayTag 1.1 TableDecorators and Exporting

Export and TableDecorator
I'm not sure if this is an issue or a setting I'm missing somewhere ... any insight would be appreciated.

displaytag 1.1 :
During an excel table export, I have received java.lang.NoSuchMethodException: Unknown property 'viewUserId', thrown from PropertyUtils. getProperty() which is being used by the report generator class () .

The problem is that the TableDecorator for this particular table is not being used to access the property values, thus, as in this case, an exeception is thrown because the property 'viewUserId' does not exist on the naked row object.

Doing a little investigation into where the TableDecorator is set leads one to

TableTag.doEndTag():

    // TableDecorator tableDecorator = DecoratorFactory.loadTableDecorator(this.decoratorName);
    String tableDecoratorName = null;
    Object previousMediaType = this.pageContext.getAttribute(PAGE_ATTRIBUTE_MEDIA);
    if (MediaTypeEnum.HTML.equals(this.currentMediaType)
        && (previousMediaType == null || MediaTypeEnum.HTML.equals(previousMediaType)))
    {
        tableDecoratorName = this.decoratorName;
    }
    else if (!MediaTypeEnum.HTML.equals(this.currentMediaType))
    {
        tableDecoratorName = this.properties.getExportDecoratorName(this.currentMediaType);
    }
    TableDecorator tableDecorator = this.properties.getDecoratorFactoryInstance().loadTableDecorator(
        this.pageContext,
        tableDecoratorName);

    if (tableDecorator != null)
    {
        tableDecorator.init(this.pageContext, this.list, this.tableModel);
        this.tableModel.setTableDecorator(tableDecorator);
    }

You can see here that if the "currentMediaType" is HTML (and the "previousMediaType" is null or HTML)*,
then use the "tableDecoratorName" specified by the tag attribute(decorator="") in the JSP.

The proper TableDecorator is returned and everything works as expected.

If the "currentMediaType" is Not HTML, for example "excel" or "pdf", then you can see the "tableDecoratorName" is pulled from, ultimately the displaytag.properties file.

The key getExportDecoratorName(String mediaType) uses,
ends up being

export."mediaType".decorator , or in this example
export.excel.decorator

or null if this property doesn't exist (as it does not by default).

This is where I have become confused about the programmers intentions.
If, for example, I set the property

export.excel.decorator=com.myco.decorators.UserTableDecorator

all tables attempting to exported in excel would use the same UserTableDecorator, would they not?
Which only works if UserTableDecorator is the only Decorator.

What is export.excel.decorator used for?

If it's used as a runtime replacement for the TableDecorator, obviously it needs to be by table.

I would prefer to use the <displaytag:column media="" attribute to define export tables and have it pick up the same TableDecorator used to generate the HTML view; allowing me to just add new virtual properties to the same TableDecorator.

Any insight would be helpful to where to go with this (i.e. workaround vs. patch)

Thanks
andrew