createpackage.pl for Symbian cannot find correct location of self-signing .cer/.key when run under /epoc32/tools/

If we want to use Qt/qmake under a platform kit we register qmake under /epoc32/tools/qmake.exe with some IDE or on cmd-line. This works for building, except in the case of self-signing where the createpackage.pl script presumes that the .cer/.key reside in a parent directory from its (the .pl script) current location --> /src/s60installs/

This won't work for platform kits because those certs live under \sf\mw\qt\src\s60installs\
I think if the QT_INSTALL_PREFIX was able to be used it could work in either case where qmake is under the <SDK>/bin/ folder or under the <SDK>/epoc32/tools/ folder