How use Associations created by Me.

Hi guys

I need to control the inclusion of data between two tabs NWBC.

I created this tabs and i created the association in cust_ui.

I tried to use it :

when i 'm in determination of tab A i need to see data inserted in tab B.

DATA: lt_nf TYPE zenh_t_nf1.

     io_read->retrieve_by_association(

       EXPORTING

         iv_node                 =     is_ctx-node_key

         it_key                  =     it_key

         iv_association          =     '0050568508D21ED59F9D0758BFC018A7' key of my created association

     is_parameters           =

     it_filtered_attributes  =     " List of Names (e.g. Fieldnames)

         iv_fill_data            = abap_true   " Data Element for Domain BOOLE: TRUE (="X") and FALSE (=" ")

     iv_before_image         = ABAP_FALSE    " Data Element for Domain BOOLE: TRUE (="X") and FALSE (=" ")

     it_requested_attributes =     " List of Names (e.g. Fieldnames)

       IMPORTING

     eo_message              =     " Message Object

         et_data                 =  lt_nf    " Data Return Structure

     et_key_link             =     " Key Link

     et_target_key           =     " Key Table

     et_failed_key           =     " Key Table

     ).

But it didnt work.

Tha table is empity.

What is wrong?

Do you have tutorial or links with informations about associations?

Thanks