Thank you Marc , as I can see from your reply I should have stated that I am working with categories module, which I belive is NOT the official Drupal category functionality. So thats why I maybe am being stucked with the problem. Should I start all over or is it worth trying with this module?
What I am trying to do is to set up a dinamic category tree using category.module, sorry (:  I dont want to create the full tree in advance because of the extension,  but let the user create the path he/she wants to see choosing from a combo. After path creation I also want to add a story node  to that path and that is the point where i am stucked.
Is this idea mad or bad ?
Thank you.
Manfredo

Marc Poris wrote: 
Manfredo,

Start here:  http://drupal.org/node/299

Then go down to the "Modules that do more with categories" post.  
Install some of the modules that look like they may be doing something 
similar.

Take a look at the function taxonomy_save() in taxonomy.module.  Create 
some nodes, put them in categories (I think you're talking about using 
the core taxonomy module), and walk through the code that saves the 
nodes to the database.

These things ought to get you started ... if you've already done all 
that, then we'll need a little more information as to what your exact 
problem is.  When you've got it figured out, it will be worth a post on 
Drupal.org if you think you'll be able to help someone else out.

Marc



Ingeniería de Sistemas wrote:
  
Hello:
I am new to the list and am wondering why I cant get so little support 
with Drupal (either thru forum/documentation/search ), so this is my 
last attempt to get somewhere.

I am creating new nodes in my module  which I want to relate to an 
existing category.
Does anybody  know how to do this?
Thank you
Manfredo Hopp