Bootloader doesn't work from external HD

[La bla bla]

Hi..

I just wrote a long post and accidentally closed the browser. so to make a long story short:

I have Windows 8 and Ubuntu installed on my Lenovo B570. I have Lion (currently 10.7.1, fresh install. in the process of upgrading) on my WD a bit old external hard drive.

 

Windows and Ubuntu uses grub2 boot loader.

 

After installing OSX, I tried installing several boot loader to my external drive, none works.

It won't do anything, just immediately goes to the grub2 loader which OSX of course isn't in it.

 

2 questions:

-Why can't I boot from my external HD which has Lion on it? (I always boot from the installation USB which has chameleon on it)

 

-Is there a way maybe to have Lion appear on the grub2 loader?

 

Thanks,

Carmel