valgrind + osx

I just started implementing unit tests for my hobby project and I wanted to integrate valgrind into my testing process, especially since it recently got fully supported on OSX. So I tried the MacPorts installation of the package. Unfortunately, I run a 10.6 64-bit os and so the packages that are automatically built come out as x86_64 executables. But in my hobby project, I keep everything 32bit. And even though the valgrind documentation indicates that it should work with both 32 bit and 64 bit executables, I couldn't get it to work. It just produced errors like:

valgrind: ./a.out: cannot execute binary file

So, my current solution is that I've downloaded the source and compiled it with only 32 bit support. Instructions are found here with the change:

./configure --enable-only32bit

And I keep the working 64 version available so I can still test all executables.

If anyone knows what I should do to get both 32/64 bit support in the same valgrind executable, please let me know!