Solved the problem myself.
I added following code to the DO_PREPARE_OUTPUT method of view Salesemployee
CALL METHOD SUPER->DO_PREPARE_OUTPUT
EXPORTING
IV_FIRST_TIME = ABAP_FALSE.
DATA: lr_entity type REF TO cl_crm_bol_entity,
lv_sales_emp TYPE string,
lv_emp type bu_partner,
lv_account type bu_partner,
lv_account_int type bu_partner,
lr_core type ref to cl_crm_bol_core,
lr_account TYPE REF TO cl_crm_bol_entity,
LV_TRANSACTION TYPE REF TO if_bol_transaction_context.
DATA: lv_descr TYPE bu_descrip.
lr_core = cl_Crm_bol_core=>get_instance( ).
*get the customer number
try.
lr_entity ?= me->typed_context->salesemployee->collection_wrapper->get_current( ).
catch cx_root.
endtry.
lv_account = lr_entity->get_property_as_string( 'BP_NUMBER' ).
lv_sales_emp = lr_entity->get_property_as_string( 'SALESEMPLOYEE' ).
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
EXPORTING
INPUT = lv_account
IMPORTING
OUTPUT = lv_account_int.
if lv_sales_emp is INITIAL.
lr_entity->switch_to_change_mode( ).
*Get the Sales employee from the customer
Select partner2 into lv_emp from but050
where partner1 = lv_account_int and reltyp = 'BUR011'.
endselect.
*Set the sales employee
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
EXPORTING
INPUT = lv_emp
IMPORTING
OUTPUT = lv_emp.
lr_entity->set_property( iv_attr_name = 'SALESEMPLOYEE' iv_value = lv_emp ).
CALL FUNCTION 'CRM_BUPA_DESCRIPTION_READ'
EXPORTING
iv_partner = lv_emp
IMPORTING
ev_description_name = lv_descr
EXCEPTIONS
OTHERS = 0.
IF lv_descr IS NOT INITIAL.
lr_entity->set_property( iv_attr_name = 'EMPLOYEE_NAME'
iv_value = lv_descr ).
me->typed_context->salesemployee->collection_wrapper->publish_current( ).
lr_core->modify( ).
LV_TRANSACTION = lr_core->get_transaction( ).
LV_TRANSACTION->save( ).
LV_TRANSACTION->commit( ).
ENDIF.
endif.
endmethod.