Help please!

Hello,

I'm looking for help with setting some default avatars to my users that haven't yet set one for themselves.

I've tried the Default Avatar plugin over at MyBB but it doesn't work for some reason.

Could someone help me with this?

ive been using that plugin on my forums and its working fine for me
i use this on a 1.8.5 installation and costum theme
http://mods.mybb.com/view/default-avatar/

That's already built in 1.8?