[support] Hide some vocabulary fields in node creation for some roles

[Pierre Rineau]

Hi,

I'm looking for a module which permits to disable some taxonomy fields
on creation and edition forms.

I use taxonomy to tag some content for admin reasons, and I need users
to see it, but not to edit it.

I tried TAC_lite which did not feet with what I want to do.

I also tried TAC which do the trick, but there is a anonying bug:
I have a content type with a vocabulary containing this terms: "normal"
and "premium".
Users which create this nodes dont have the choice, they have to put
"normal", which works.
Then, a admin can change and select "premium".
Then, when the user edit his node, he can't save it because he have to
switch it to "normal" again.

I want a taxo vocab not to be editable by users, but only by some role.
I dont want any other functionnality than that.

Is there any module that can do only this, disallow a role to change a
vocab, but allow him to edit the node anyway ?