QTreeWidget::setColumnCount produces non empty headers

I'm trying to use QTreeWidget with several headers and one of them should be empty. I've made a ui file in designer application and I'm using uic to create ui_*.h file.
uic creates retranslateUi function with calling setText over every field in QTreeWidget header except empty. So, it assumes that by default every header field is empty (imho, it's correct behavior).
However, http://qt.gitorious.org/qt/qt/blobs/4.7/src/gui/itemviews/qtreewidget.cpp#line200 shows that fields is not empty but filled with field number (imho, it's incorrect).
So, I can't make QTreeWidget from designer, where one of header field is empty.