hi anda,
if you have data in your chart, that's supposed to be scaled to the secondary y-axis, just move the plot there, here's an example:
xls = actxserver('Excel.Application');
xls.Visible=true;
a=num2cell([(1:10)' (1:10)' (10.^(1:10))']);
wb=xls.Workbooks.Add;
set(wb.ActiveSheet.Range('$A$1:$C$10'),'Value',a);
crt=wb.ActiveSheet.Shapes.AddChart(75);
getscale(crt)
s2=crt.Chart.SeriesCollection(2);
set(s2,'AxisGroup','xlSecondary');
if you just want the other axis with only one plot, you need some dummy data.
regards
julian