Hmm, RW should not use Qt, if it does search for Qt then thats definitely an error.
Regarding RWS then the scripts in the cmake system is not always able to autodetect where Qt is installed/placed. As you describe and as is described in cmake the script FindQt/FindQt3/FindQt4 needs qmake in the system path.
You could possibly add the directory of your qt bin folder to the system path like this (notice not tested)
SET($ENV{PATH} "$ENV{PATH};c:/qt4/bin")
/Jimmy