Regarding the mac question, 2 things.
You might have to take all the tremulous stuff out of the disk image, and actually move it onto your desktop. so when you click that wierd white box, and it mounts and everything, copy the folder named tremulous-gpp1 and move it to your desktop. you cant write to or modify things when they are in the disk image(the white thing you mounted), so copying it and moving it out of the disk image should let you mod it.
If that doesnt work, i have no idea, although IIRC macs basically use the files located in your user/library/applicationsupport/tremulous. so you should try modifying those and see if that works, rather than modifying the disk image. although im not sure if 1.2 changed this, or if this was completely wrong in the first place.
just my 2 cents, im not a tech guru.
