API dox misses to mention that type of a saved contact can/should not be changed

The unit test tst_QContactManager tests that the engine backend restricts the change of the type of a contact which has already been saved as another type: "// Try changing types - not allowed", see https://www.qt.gitorious.org/qt-mobility/contacts/blobs/48c5131/tests/auto/qcontactmanager/tst_qcontactmanager.cpp#line1321

But I could not find this restriction mentioned in the API dox, at least where I would have it expected, like
http://doc.qt.nokia.com/qtmobility-1.2/qcontact.html#setType
http://doc.qt.nokia.com/qtmobility-1.2/qcontacttype.html

So please add this there (unless the test is wrong about this).