Controlling py.exe launcher on Windows

[Edward Diener]

I am trying to control the default version of the py.exe launcher on 
Windows. I have the Python 2.7.8 and 3.4.1 installed with both the 32 
bit and 64 bit versions, all in different directories. I assume that .py 
and .pyw files are associated with the py.exe launcher.

I am trying to control which version starts through a py.ini file in the 
same directory as the py.exe file in the 3.4.1 version last installed.

If I specify in the [defaults] section of py.ini:

python=3.4

then launching py.exe will show:

Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 10:45:13) [MSC v.1600 64 
bit (AM
D64)] on win32

If I specify:

python=3.4-32

then launching py.exe will show:

Python 2.7.8 (default, Jun 30 2014, 16:08:48) [MSC v.1500 64 bit 
(AMD64)] on win
32

Is it really true that I cannot specify the 32 bit version in the .ini 
file or am I doing something wrong here ?