couldn't find in the tkd the part which wrote, that the {-be'} can be
placed to verbs used as adjectives.

Actually, it really isn't mentioned in TKD (or I cant find it).

It's not in TKD. We've gotten it in examples. The one I can think of off the top of my head is wa'maH yIHmey lI'be' ten useless tribbles (CK).

We've also gotten -Ha' in examples: Duj ngaDHa' unstable vessel (person who is out of control) (KGT).

-- 
SuStel
http://trimboli.name