Thx NoRoBro for you quick reply.
The additional patching didn't solve the problem reinstalling did.
Here is what I did on Natty's version of Ubuntu to make it work:
  1. Uninstall:
    I uninstalled all the aforementioned programs (Qt3, Qt4 SDK 4.74, OpenSSL 1.0.0e 6 Sep 2011, qca-2.0.3, qca-ossl-2.0.0-beta-3), then I made sure to clean all my directories (/usr/local and such).
  2. Reinstall:
    First openssl, then QT Creator from Ubuntu's software repositories.
    Note that I deliberately removed my path to <QTDIR> from bashrc, and I deliberately left out QT3, to make sure that both QCA's will find qmake-qt4 in the /usr/bin and not qmake-qt3.
    I installed qca-2.0.3 without any problems.
    After the installation of QCA-2.0.3, I patched CMakelist and qca-ossl.cpp. I encountered 1 setback with the .configure from qca-ossl, it would'nt recognize the qca-2.0.3 install. Even after feeding argument --with-qca=/usr/local/qca-2.0.3 directory to the qca-ossl configure file, it would not recognize the installation. I needed to run sudo /sbin/ldconfig before the qca-ossl installation.
    After installation I ran qcatool2 plugin --debug. It provide the same results as my first post.
    I altered the .pro file to find the newly installed libraries (INCLUDEPATH =/usr/local/qca-2.0.3/) and (LIBS += -L/usr/local/lib -lqca) and CONFIG += crypto
    Then somehow my code (main.cpp) started working.
  3. Conclusion:
    It must have been a linker problem, maybe even a permission problem on a library or a missing library (I have small kids playing on my computer).