Kollection 3.7.1 + KTML 4 on many-to-many textarea?

Hi all,
I cannot make KTML 4 to show up on a textarea created by a many-to-many
kollection wizard.

I created the MTM relation and it works perfectly with simple textareas.

But when I replace that textarea with KTML 4, the related field is not
displayed at all.

Why?

Strangely enough, KTML_lite 3 works but it brings other problems (it
doesn't allow to keep a field really empty (it always puts <p></p> tags on
empty fields).

is there a workaround?

tia

tony