Custom Attribute is not saving

Hello

I'm new to CRM but I need your help.

I need to add a custom field for service locations => Technical Object Details

The field should be add here:

First I've tried to use AET but I can´t use it in this case (no "Create field" button appears):

I've created a new enhancement set: "ZCRM_TEST2" and in table BSPWDV_EHSET_ASG uses this one as default:

In BOL explorer I've seen that ConnectionObject uses structure "CRM_ISU_TEC_CO". This structure has an include CI_CON, so I added my field here:

Then I've create an enhancement for the view "IUICOBJD/ConnectionObject":

Here I created a new Model Attribute for CCAA field:

In the generated code the only changes are:

Method WD_CREATE_CONTEXT to comment linne super->wd_create_context( ).

Methods GET_ SET_ GET_M and GET_I are also generated but I made no modification in them.

Then I add the attribute to the view.

The problem is that the value is not saved:

Thank you vey much.