It will be harder to generate sales from Euro 2008 with no Home Nations involved but it won't be impossible. You just need to be more creative and inventive and work harder to get your customers excited about the tournament.
Why not use the games to create interest with competitions like score predictions for the time of the first corner or the last goal. Run a quiz between the first round matches with a half hour gap between the late afternoon game and the evening game. Alternatively use the whole idea of "Euro" to host some themed events. Why not stage a themed food night offering Italian pizza, German sausage or Portuguese fish. And if that doesn't appeal, why not stage a "Eurovision" Karaoke night to find your local singing stars? This would be a really fun way to get your customers involved and to generate additional footfall into the pub. It would also be a great story that would be of interest to your local paper, so give it a go.
And, don't forget that there will be some 'footie widows' out there, so if you're not a sports pub and you have a strong food offer, why not host a special 'sports free' night for your female customers?