Hi Sergio,
Could you please use below code..
SELECTION-SCREEN : BEGIN OF LINE,POSITION 1.
PARAMETERS:
p_a RADIOBUTTON GROUP grp1 DEFAULT 'X' user-COMMAND switch.
SELECTION-SCREEN: COMMENT 50(3) text-001 FOR FIELD p_a.
PARAMETERS: p_yes RADIOBUTTON GROUP grp2 DEFAULT 'X' USER-COMMAND switch.
SELECTION-SCREEN: COMMENT 50(3) text-002 FOR FIELD p_yes.
SELECTION-SCREEN : END OF LINE.
SELECTION-SCREEN : BEGIN OF LINE,POSITION 1.
PARAMETERS:
p_b RADIOBUTTON GROUP grp1.
SELECTION-SCREEN: COMMENT 50(3) text-003 FOR FIELD p_b.
PARAMETERS: p_no RADIOBUTTON GROUP grp2.
SELECTION-SCREEN: COMMENT 50(3) text-004 FOR FIELD p_no.
SELECTION-SCREEN : END OF LINE.
Just put proper selection text.
Hope this helps.
Regards,
Supratik