Absolute path for ProfileDrectory etc

Hello,

I would like to know if it's possible to make paths in files like
FirefoxPortable.ini accept absolute values. Clearly, I'm using
Firefox and I want to store the program itself on the hard drive,
keeping the profile on my flash drive (or my network drive).
So I would like the example below would work:

[FirefoxPortable]
FirefoxDirectory=C:\App\firefox
ProfileDirectory=G:\Data\profile
SettingsDirectory=G:\Data\settings
PluginsDirectory=G:\Data\plugins

This could save some space on the flash drive and speed up the
startup process. Any suggestions on how to do that?

Thanx in advance.