You do need one of the latest versions of the upcoming version 2.0. The alpha has been released a couple of weeks ago, but you can also go for a recent snapshot.
Those can be found here: ftp://ftp.qt.nokia.com/qtcreator/snapshots/

After adding the Qt version, does it recognize it correctly as a Maemo version? Switching to the Maemo target should only display one Toolchain then.