set checkbox depending on dropdown-box crm web ui

[olivgerb]

In ui component "BUAG_DETAIL" i want to set a checkbox depending a value from a dropdown-box.

My code sets the value for the checkbox correctly but when i save and reload or look in backend the checkbox is still empty. What should i do to save the value in the checkbox permanent?

I did 3 things:

- DO_HANDLE EVENT:

CASE htmlb_event_ex->event_server_name.
 WHEN 'VERTYP_SELECTED'
  eh_onvertyp_selected( htmlb_event = htmlb_event htmlb_event_ex = htmlb_event_ex ).
 ...
ENDCASE

-GET_P_VERTYP:

CASE iv_property.
 WHEN if_bsp_wd_model_setter_getter~fp_fieldtype.
  rv_value = cl_bsp_dlc_view_descriptor=>field_type_picklist.
 WHEN if_bsp_wd_model_setter_getter=>fp_server_event.
  rv_value = 'VERTYP_SELECTED'.
ENDCASE.

-EH_ONVERTYP_SELECTED

lr_current = me->ztyped_context->BUAGISUFIELDS->collection_wrapper->get_current( ).

CHECK lr_current IS BOUND.
lv_typ = lr_current->get_property_as_string( EXPORTING iv_attr_name = 'VERTYP' ).

IF lv_typ = '0002'.
 lr_current->set_property_as_string( EXPORTING iv_attr_name = 'ZLEER' iv_value= 'X' ).
ELSE.
 lr_current->set_property_as_string( EXPORTING iv_attr_name = 'ZLEER' iv_value= ' ' ).
ENDIF.

lr_core = cl_crm_bol_core=>get_instance( ).
lr_core->modify( ).

I'm thankfull for hints...

thanks and regards

Oliver