Highlighting a Field in A Table Control

I have some code I've written in CRM that in theory should highlight the field where I want the user to be directed to.

The problem is, the field in question is in a table control i.e. the Responsible Institution in the Identification numbers tab in the BP transaction.

I have tried this for a non-table control field and the field text changes colour but the cursor isn't placed in the field.

Neither happens when I specify the field on the table control.

Is it that this just simply cannot be done or is there another approach?

My code below:

CALL FUNCTION 'BUS_MESSAGE_STATUS_SET'

EXPORTING

msg_coll_status = '1'.

CALL FUNCTION 'BUS_MESSAGE_STORE'

EXPORTING

ARBGB = gc_msg_arbgb

MSGTY = gc_msg_error

TXTNR = '000'

MSGV1 = 'You cannot use numerals in the institute name: '

MSGV2 = gt_but0id-institute

MSGV3 = '. Please change this.'

TBFLD_STRG = 'GT_BUT0ID-INSTITUTE'.

Many Thanks

David