about comment #2:
if you have "Truecrypt Boot Loader installed in the MBR and Grub2 on sda1", as far as I know, Grub2 doesn't chainload anything.
You just have Truecrypt Boot Loader that starts first and then, pressing Esc Key, you can skip it and go to Grub2.
So it's Truecrypt that calls (chainloads?) Grub2 and not viceversa. But this bug is about Grub2 ability to chainload Truecrypt Boot Manager.
So no solution yet.