Trouble building a sample (4.6)

[Asperamanca]

I also tried building the sample in Creator 1.2.0 (using QT 4.6.0 beta again, since the sample won't work with an older QT version).

I noticed right away that the environment variables shown in "Project" - "Build Environment" are my regular system environment variables, not the ones from the QT command line. This is the case even if I start QTCreator from the QT command line.

So I tried checking the "Clean environment" boxes in both Debug and Release mode, and tried building the Debug mode first. I also replaced nmake with jom

Both qmake and then jom crashed.
QMake with the following call stack:

MSVCRT! 77c3f463()
QMAKE! 0047b7dc()
QMAKE! 00553708()
QMAKE! 005f54c2()
QMAKE! 005f4d21()
QMAKE! 00456167()
QMAKE! 00579624()
QMAKE! 00438726()
QMAKE! 00438b3e()
QMAKE! 0040124b()
QMAKE! 00401298()
KERNEL32! 7c817077()

jom without any debugging information at all.

(EDIT): When unchecking "Clean Environment", the behaviour is just like in Creator 1.3.0 beta. When checking "Clean Environment" in Creator 1.3.0 beta, qmake crashes, just like in 1.2.0.
So the Creator version does not seem to have anything to do with it (/EDIT)

Is there an article somewhere that describes in detail how to build yourself a clean QT environment (with multiple QT versions), even if you have other debuggers installed as well? I fully understand that my system isn't very cleanly installed, but as long as I don't know exactly what QT and Creator need and will use, I expect to run into trouble.

Other than that, is there a way to make Creator behave exactly as the QT command line, as far as building is concerned?