I had in my pc Nokia Qt SDK 1.0 for developing and creating applications for my loving n900, and i got surprised when i installed this latest version of the Qt SDK 1.2 and didn't see the maemo pr1.3 target...
There is Maemo support in Qt SDK 1.2.1, you just need to download it. Open Qt Creator, go to Help -> Start Updater and Maintain Qt SDK window will appear. Choose Package manager and hit Next. Expand Development tools, choose Maemo toolchain and the rest should be obvious.
Note: after installing was done, I had to restart Qt Creator twice so I could add Maemo 5 as target platform.
i found the option to enable madde in qtcreator 2.8 but i've got to install sdk still for it to work correctly. just need to find best way to do it for my distros. No hurry to do it at the moment though.