in the object editor in the units tab select the unit you want to change and search for the entry (its pretty much at the end of the list if i remember correctly)
It depends on what other's attack is not armor. You could try making the armor an upgrade and changing it's the defense upgrade bonus in "data - effect 1".
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.