cftool and confidence bounds

Hi,

I'm fitting a curve to some points with the matlab's cftool. The type of the fit is a simple sum of sines function: a*sin(b*x+c) In the results I get the coefficients a,b and c with 95% confidence bounds.

I am trying, without success, to do the same fit but with 99% confidence bounds for the coefficients. Is it possible to control the confidence bounds with cftool?

Thank you!

Alya