C4 kills not registering for need only one assignment bf4 xbox 360

Do it as Recon, if it's the same as PC, the C4 kills aren't counting as support.

I have been haveing the same problem.
Just did it as recon and it worked, it was the last gun i had to unlock and the last thing i needed for the "complete all china riseing assinments" trophy

Its still stupid that i dont know and will never know how many C4 kills i have, i mostly use C4 on my support.