Sorting by reverse index order

[Dragan]

Hi,
I'm trying to do sorting by reverse index order but I get this
Exception:

java.lang.IllegalStateException: Illegal sort type: 1
at
com.browseengine.bobo.sort.SortCollector.getNonFacetComparatorSource(SortCollector.java:
72)
at
com.browseengine.bobo.sort.SortCollector.getComparatorSource(SortCollector.java:
100)
.............

I am just setting:
Sort sort = new Sort(new SortField(null, SortField.DOC, true)));
boboBrowseRequest.setSort(sort.getSort());

I didn't add FacetHandler for docId.
Is there any way to use Lucene index order sorting in this case?