Qt VS Tools 2.6 moc not finding interface

[thePoet]

The new version of QtMsBuild is failing on this code:

#include <QtUiPlugin/QDesignerCustomWidgetInterface>

class MyClass : public QObject, public QDesignerCustomWidgetInterface
{
	Q_OBJECT
		Q_INTERFACES(QDesignerCustomWidgetInterface)

With "Error: Undefined interface"

An absolute path will in the include will work. Also, this worked with the version of QtMsBuild that came with Qt VS Tools 2.5. Not sure if there is any workaround. This is the only file I'm having issues with.