A forthcoming summit between the European Union and Balkan nations can only be a success if both Serbia and Kosovo attend the meeting, the EU's enlargement commissioner Stefan Fule told the German Press Agency dpa on Friday. Belgrade is insisting it would boycott any event where its former province Kosovo is represented at state level, since it does not accept its secession. EU leaders are working on a compromise, as they want to avoid a repetition of the March fiasco of the last Balkan conference in Brdo, Slovenia, which Serbia boycotted at the last minute. "I hope very much that the foreign ministers (of Balkans countries) will not miss this opportunity to make the point that they could turn regional cooperation into an inclusive process, making sure that everybody is behind the table," Fule said in an exclusive interview with dpa. Fule, who present in Brdo, implicitly confirmed reports that he would not attend the June 2 meeting in Sarajevo if Serbia and Kosovo were not both present. "I'll be participating in each and every conference which is based on the principle of inclusivity and pushes the regional cooperation on step forward ... and I hope that in the case of this conference it will be even two steps forwards," he said. The EU's foreign policy chief Catherine Ashton, who stayed away from the last Balkan conference, is also imposing the same conditions. "Sarajevo is about regional cooperation, if not everybody is at the table it does not make sense," a source close to her told dpa. A compromise to let Serbia and Kosovo share the same table may have been found this week, as Italian foreign minister Franco Frattini visited Belgrade and Pristina to propose the so-called "Gymnich" solution. The formula, named after the format given to informal meetings of EU foreign ministers, would see participants to the Sarajevo conference represented only by their name, without any official reference to their country. It remains to be seen, however, what space will be given to Kosovo's UN administration (UNMIK), which according to Belgrade is still the official ruler over the province, while Pristina sees itself as a fully sovereign government. Kosovo is particularly delicate issue for the EU since five of its 27 member states, including the bloc's current president Spain, have not recognized its independence. Fule appeared relaxed about the persisting squabbles in the Balkans, despite disputes between Croatia and Slovenia, Macedonia and Greece and ethnic tensions in Bosnia-Hercegovina also hampering Euro-Atlantic integration. "People forget that we have seen the most destructive dissolution of one state in that part of Europe ... if you look and compare the current situation with what we faced 15 years ago, i think you could say: 'wow, what an achievement'," the commissioner stressed. He said he was "confident" that Slovenia would still ratify a territorial agreement with Croatia despite a planned referendum against it, and indicated that the so-called mobile-phone wars in Kosovo, with Serb operators being shut down, was "not a political issue, but a commercial one." The former Czech diplomat said it would be "not only unwise, but impossible" to give a precise date for Croatia's EU accession, but confirmed the commission would do "everything to make it possible" to help Zagreb achieve its own target of completing accession talks by 2010. That would see the Balkan nation enter the EU around 2012, given the time necessary for the ratification of its accession treaty by the existing 27 members of the bloc. Fule also reiterated that visa-liberalization for Bosnia and Albania was forthcoming, though he did not say whether the positive news would be given at the Sarajevo conference. "Both countries have made a tremendous job in recent weeks and months ... on that positive assessment, I think it's logical to expect a positive recommendation," he said.