MSVC2008 : win 32 and win64 installation

hello
i am running qt 4.8.1 and MSVC++ 2008 on a 64 bit win7 computer. Since my application relies on some libs and dlls compiled for a 32 bit machine and I want to get the qt libraries for 32 its i am running from MSVC command prompt the following

nmake clean
configure -debug-and-release -opensource -shared -no-qt3support -qt-sql-sqlite -no-webkit -no-script -platform win32-msvc2008
nmake

all of this ran smoothly.

If I look at the MSVC project files I see the linker relies on the $(QTDIR)/lib and I see QTDIR is currently set at c:\qt\4.8.1 and lib files qtcore.dll, lib etc. are correcly there

I then open my MSVC solution with win32 configuration and I got the error 'There is no Qt version assigned to this project for platform Win32' ...
If I create a new x64 configuration I can compile the program but of course I cannot link my thrid-party lib files

please help: I probably miss some obvious steps or I do not fully understand the 32-64 bit dilemma

one more question: what hould I do to maintan *both* 32 bit and 64 bit Qt? It looks like they are compiled in the same $(QTDIR)/lib directry. should I manually rename the directories and redefine the QTDIR env variable? I was figuring out this is handled smoothly by the installation process

thanks much to who'll help me on this