Poland's President Lech Kaczynski will sign the European Union's Lisbon Treaty into law on Saturday, Reuters quoted a presidential aide as saying today. "The signing ceremony will take place on Saturday. It will include international guests," aide Tomasz Brzezinski said. Kaczynski's signature would leave only Czech President Vaclav Klaus still to approve the document after Irish voters overwhemingly backed the treaty in a referendum last Friday.