Hi pooja,
actually standard service request numbers are configured in spro->crm->transactions->Settings for Service Requests->Number Ranges. here they are maintain service request,incident,problem number ranges..
so when ever your creating any service request then that number range will appear in that object id.
you have to get that object id in your custom field get_method and based on that you have to change your number..
example:
current = me->bo.
current->get_property_as_string( EXPORTING iv_attr_name = 'OBJECTI_ID' RECEIVING rv_result = lv_id ).
here you will get object_id based on that you have to write your own logic to display custom value.
" write your custom logic to populate custom field. pass that custom field value into returning parameter.
value = custom_value.
Thanks & Regards,
Srinivas.