[Enigmail] enigmail with portable gpg

[Alan Yoder]

I've got an odd situation, the version of gpg I am having to use is 
required to be on my usb u3 drive.
The version of thunderbird with enigmail is installed on the same drive.
In order to use gpg I have a .bat file which I swiped from gpgtogo, it 
sets a home directory where the gpg.conf and ring files are located, off 
of the gpg dir itself, g:\gpg\home
Upon running this .bat file, I have command line access to gpg, I can do 
what ever I like to the gpg I've got set up.
Thunderbird doesn't share this however, it still insists on looking at 
c:\doccuments and settings\username\... for its information.
My question, why if I can get gpg to recognize where I want it to look 
by running this .bat file would not thunderbird and enigmail be happy 
with using the same information?
I know this could be fixed by either installing gpg to the local 
machine, or modifying autoexec to include the home environment variable, 
though these solutions would make it a nonportable solution.
Also, I'm not allowed to make such modifications to the computer here in 
the library.
If I run a .bat file, is this in a separate space from thunderbird and 
enigmail and that's why it won't look where I want it to? This is the 
only thing I can think of that would cause this behavior.