splines, polyfit and polyval, wrong coefficients?!?

Good morning all together,

I have a question concerning the spline function and it´s coefficients (MATLAB R2012b). I have created a function out of two clothoids which looks like this.

Now I want to evaluate this function piecewise by fitting a cubic spline. Afterwards I took a look at the coefficients and tried to find the piecewise polynomial function:

y = spline(xges,yges);
xev = linspace (0,1,10);
hold on

for i =1:length(y.coefs)

      br = y.breaks(i:i+1); 
      xxp(i,:) = linspace(br(1),br(2),10);
      cf = y.coefs(i,:);
      yp(i,:) = polyval(cf,xev);

%     ypp (i,:) = ppval(y,xxp(i,:));

     plot(xxp(i,:),yp(i,:),'.g') ;

end

But it doesn´t fit the function. The piecewise polynomial functions are wrong. So are also the coefficients of the cubic spline wrong? Or am I doing some mistake by evaluating the piecewise polynomial functions? It´s also a little bit weird that the spline looks perfect, when I´m not using the polyval, but the ppval function. (Blue line is with ppval, green lines with polyval)

I hope you can help me

Thank you in advance,

David