Set up a GUI status at ALV with class's implementation

Hello,

How can I add a gui status with a new pushbutton to an ALV screen that was implemented within class decleration ??

TRY.

CL_SALV_TABLE=>FACTORY(

IMPORTING

R_SALV_TABLE = GR_TABLE

CHANGING

T_TABLE = GT_REP ).

CATCH CX_SALV_MSG.

ENDTRY.

Thanks in advance,

Rebeka