User defined type - analyze problem

Hi *,
I have a little problem with a user defined type:
I constructed a type called "pointnd" which represents a multi-dimensional point. This point is subsequently used as an array type in another user defined type, like the following:
CREATE TYPE document AS (words tsvector, points _pointnd);

After some time, I have some problems with this type, obviously. The postgres process keeps on reporting the following line:
ERROR: could not identify a comparison function for type pointnd
CONTEXT: automatic analyze of table "test.public.documents"

I read somewhere, that this can be solved by preparing a operator class for btree and passing a comparison function for equality there. I did this with the following lines:
CREATE OPERATOR CLASS pointnd_btree_class
DEFAULT FOR TYPE pointnd USING btree AS
OPERATOR 3 =(pointnd, pointnd)
;

However, the postges process still reports the same errors after having set up the btree operator class.
How can I solve this issue?

Best regards
Carsten Kropf