Emissive object w/ Bloom + Alpha channel Issue

[joeydbooth]

Hi guys, I got this problem with a simple emissive object and the alpha channel i get out of it...
The scene does have motion blur, depth and bloom, should all of this generate a clean alpha or do I have to use a work around?

Basically, I just want I this sort of effect :

black-bg example

But when I render it with alpha, everything outside the head, doesn't have the wanted look...

alpha example

Am I missing something?

I've attached my scene file, thanks for the help!