How to add text to radio buttons

SELECT-OPTIONS: data FOR zsl_cp_header-pstng_date.

SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN COMMENT 1(11) FOR FIELD r1.
PARAMETERS: r1 RADIOBUTTON GROUP rad1 DEFAULT 'X'.
SELECTION-SCREEN END OF LINE.

SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN COMMENT 1(11) FOR FIELD r2.
PARAMETERS: r2 RADIOBUTTON GROUP rad1.
SELECTION-SCREEN END OF LINE.

SELECTION-SCREEN:END OF BLOCK block01.