[CMake] GCC version change problems

[Corrie]

Hi all,
I'm trying to get Cmake to compile some VTK programs with GCC/G++ 4.0  
on an iMac G3 running OSX 10.4.8, Xtools 2.4.1 and CMake2.4 patch  
4.    I've used "sudo gcc_select 4.0" to select my system compiler  
preference.  However, CMake doesn't seem to allow me to change to GCC  
4.0.  If I edit the CMAKE_CXX_COMPILER and CMAKE_C_COMPILER's in  
cmakecache.txt to g++-4.0 and gcc-4.0, respectively, they revert, in  
the file, to GCC 3.3 when CCMake is told to configure.  The same  
thing happens when I make the change through CCMake.  Yet when I run  
gcc -v, I'm told "gcc version 4.0.1 (Apple Computer, Inc. build  
5367)".  Can someone tell me what I can do to fix this?  Thanks.
Corrie