Getting the error on the integral of a fit

Dear RooFitters,

I am looking for the best way to obtain the error on the integral of a fitted function from RooFit. I already obtain the value of the integral like this:

RooAbsReal *intbkg = w::bkg.createIntegral(w::x,Range("signal"));

But the function getError() is not defined on a RooRealIntegral, so what would you recommend?

Thanks in advance,