I'm having issues getting the qwt widget to work correctly with Qt-Creator

I'm having issues getting the qwt widget to work correctly with Qt-Creator

I'm having issues getting qwt 6.1.0 to work correctly with Qt-Creator
5.1.0. It works correctly when I launch the stand alone version of
Qt-Designer and everything compiles and runs correctly when I use
Qt-Creator. However the designer that is built into Qt-Creator does not
display the qwt widgets correctly on any forms nor give me the option to
add new qwt widgets.
I'm using Qt Creator 5.1.0 for Windows 64-bit (VS2012 with OpenGL). I've
also downloaded and compiled Qwt 6.1.0 with the aforementioned Qt-Creator,
by simply opening the qwt.pro file and compiling it. Once it was compiled
I used the 'nmake' and 'nmake install' commands from the visual studio
command prompt as directed in the Qwt instructions
(http://qwt.sourceforge.net/qwtinstall.html). I then copied the
qwt_designer_plugin.dll to the
C:\Qt\Qt5.1.0\Tools\QtCreator\bin\plugins\designer\ and
C:\Qt\Qt5.1.0\5.1.0\msvc2012_64_opengl\plugins\designer\ directories.
Does anyone have any suggestions? I can manually launch Qt-Designer and
just compile with Qt-Creator, but it is kind of annoying to have to
constantly switch back and forth and not be able to use the designer that
is bundled into Qt-Creator.