It's not exactly the same issue: #845173 reporter never got his Skype icon because he was missing sni-qt:i386. But if you don't feel like filing a new bug, please un-dupe it. Before you do so, be sure to test with a version of Qt >= 4.7.4-0ubuntu5 as it contains a fix for hp-systray which could very well be the cause of your problem.
It's not exactly the same issue: #845173 reporter never got his Skype icon because he was missing sni-qt:i386. But if you don't feel like filing a new bug, please un-dupe it. Before you do so, be sure to test with a version of Qt >= 4.7.4-0ubuntu5 as it contains a fix for hp-systray which could very well be the cause of your problem.