Vadim, are you sure this line works? It gives me an error, stating that Func.t() is of type cv::MatExpr (Mat) and as such does not have .convertTo() method.
The simple solution would be to do something like
    Mat FuncT=Func.t();
    Func.convertTo(bigC.colRange(...),CV_64FC1);
Now, while I've been thinking about this, I did not employ this solution because as far as I understand openCV matrix management system, the "Mat FuncT=Func.t();" line will make a DEEP copy of Func and I'm simply too greedy to let this happen:)
Anyway, that's a minor issue and I will do as you say, if you insist.