Mallet Percussion Key Not Changing

I am currently working on a concert band piece in which the percussion 1 player switches to vibraphone after previously playing on the bongos. Since the bongos are in a percussive clef and the vibraphone are in treble clef, after changing to bongos the key signature present with most other instruments in the band is not on the staff in the score or in the part, and the vibraphone staff looks as if it is in the key of C. (Which it is not) How would I go about adding the key signature into the mallet percussion part? Below shows the problem.

Thank you!