Extracting effective index for computed mode

Hi,

I am trying to get my head round the new (v4.0 and above) version of Matlab script language. I am mainly using RF module to compute modes of a given structure. When I use GUI, I specify number of modes to be computed, and when they are computed - in the plot parameters I can switch between the modes by choosing their effective indeces (which is equal to propagation constant divided by the wavenumber in vacuum). Now I need to sweep a parameter (say, frequency or some geometrical parameter) and I want to plot the effective index as function of the parameter. And not only plot, but use it for my further computations. Previously, in version 3.5a I used a matlab script for this purpose. There I had two commands:

fem.sol=femeig(fem,...) - to solve the problem
beta=i*fem.sol.lambda(modenum) - to extract propagation constant

What do I do in version 4.1???

I was told by a colleague that in version 4.3b I can use the following:

info=mphsolutioninfo(model);
beta=i*info.sol1.map(:,1);

However, I just tried it in 4.1 and it says there is no such method "mphsolutioninfo"!