Hi Fabio,
Good day,
Type group for ME21n,ME22n,ME23n is MMMFD.
In this we have the following custom fields.
mmmfd_cust_01 TYPE mmpur_metafield VALUE 90000000,
mmmfd_cust_02 TYPE mmpur_metafield VALUE 90000001,
mmmfd_cust_03 TYPE mmpur_metafield VALUE 90000002,
mmmfd_cust_04 TYPE mmpur_metafield VALUE 90000003,
mmmfd_cust_05 TYPE mmpur_metafield VALUE 90000004,
mmmfd_cust_06 TYPE mmpur_metafield VALUE 90000005,
mmmfd_cust_07 TYPE mmpur_metafield VALUE 90000006,
mmmfd_cust_08 TYPE mmpur_metafield VALUE 90000007,
mmmfd_cust_09 TYPE mmpur_metafield VALUE 90000008,
mmmfd_cust_10 TYPE mmpur_metafield VALUE 90000009.
So you can use these fields in your custom screen and validation can be done.
Please revert if any queries.
Thanks,
Seshadri.