Using cookies with XulRunner

Hi,

I want my embedded browser (XulRunner+JavaXPCOM) to work with cookies.
Now, every cookie is stored in a file called cookies.txt in the
XulRunner instalation directory.

I would like to store diferent cookies for different users, how can I
change the directory where xulrunner reads and stores cookies??

Has it something in common with initializating a profile??
I have done this and i don't see any diference:

  File profDir = new File("C:/temp/testProfile");
  aMozilla.initialize(this.grePath);
  aMozilla.lockProfileDirectory(profDir);
  aMozilla.initEmbedding(this.grePath, this.grePath, locProvider);
  aMozilla.notifyProfile();

Thanks,
Sergio