Mobility 1.2 Symbian: samplephonebook does not compile

When building samplephonebook for Qt 4.7.4/Symbian Belle I get the following build error:

"D:/MobilityExamples/1.2/examples/samplephonebook/contacteditor.cpp", line 161: Error: #135: class "QtMobility::QContactManager" has no member "observeContact"
m_observer = manager->observeContact(m_contactId);