using type TrussFEACrossSec{Float64} with TrussSolver

[pitipatw]

From my inspection, the type TrussFEACrossSec{Float64} is only used the generate the problem.
But it's not usable in any other format?
i.e.
You can't do add (+) or subtract it with numbers
TrussFEACrossSec{Float64}(1.0) + 1 gives an error

I want to use it with TrussSolver(solver)(<input a vector of areas>