Clear/Refresh SELECT-OPTIONS using FIELD-SYMBOLS

Hi Experts

I have a SELECT-OPTION GSO_CU03.

At one point in runtime, it's content are:

Table GSO_CU03 Table Type Standard Table[1x4(11)] | I EQ 4100 1| I EQ 4100 2| I EQ 4200

I have to refresh it's content (and refill later on)

I could have used:

REFRESH GSO_CU03.
CLEAR GSO_CU03.

But for some reason I need to use FIELD-SYMBOLS as below:

CONCATENATE GSO_CU03 '[]' INTO lv_so.
      ASSIGN (lv_so) TO <fs_sm01_so>. "the field symbol now contains the table GSO_CU03[]
      REFRESH <fs_sm01_so>. "this refreshes the select-option
      CLEAR <fs_sm01_so>. "this has no effect

As, after assignment the field symbol contains the select-option table without headerline, the clear statement as no effect.

Can anyone help me clearing it's header?

I have tried ways like:

FIELD-SYMBOLS: <fs_sm01_pa>.
  ASSIGN GSO_CU03 TO <fs_sm01_pa>. "this doesn't really assign the work area
  CLEAR <fs_sm01_pa>.

but they won't work.

Please help.

Thanks,

Aabhas K Vishnoi.