Default mkspec (qmake -spec)

The qmake tutorial mentions how to generate .dsp or .vcproj files however this does not work with the Qt SDK for Windows because it uses minGW and not VS. To resolve this a particular specification such as "qmake -spec win32-msvc2008 -tp vc" has to be specified.
It would be nice if this was somehow documented.

If the specification is not provided, i.e., "qmake -tp vc", the user gets a warning:
WARNING: Unable to generate output for: <project file name> [TEMPLATE vcapp]

Searching in the following documentation pages doesn't give a clear answer to this problem:
http://doc.trolltech.com/4.5/qmake-tutorial.html
http://doc.trolltech.com/4.5/qmake-platform-notes.html
http://doc.qtsoftware.com/4.5/qmake-environment-reference.html#qmakespec

This should be changed in the manual page for qmake tutorial that can be viewed through the Creator Help.
In addition, the document "qmake Platform Notes" should give more information about the default system specification and how to change it.