The "Caption Box" option (new in JMP 10 I think) may provide what you want.
Example:
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
dt << Graph Builder(
Show Control Panel( 0 ),
Variables( Y( :height ), Group X( :age ), Overlay( :sex ) ),
Elements(
Bar( Y, Legend( 6 ), Bar Style( "Stacked" ), Summary Statistic( "Mean" ) ),
Caption Box(
Y,
Legend( 7 ),
X Position( "Right" ),
Summary Statistic( "Mean" ),
Y Position( "Bottom" )
)
),
SendToReport(
Dispatch( {}, "", ScaleBox, {Rotated Labels( "Automatic" )} ),
Dispatch(
{},
"height",
ScaleBox,
{Min( -20 ), Max( 150 ), Inc( 25 ), Minor Ticks( 0 )}
)
)
);