How to simulate a transition with noise using the extended_path command (Dynare)?

transition .mod

var y;

varexo e;

parameters rho, sigma, ybar;

ybar = 2;
rho = .99;
sigma = .01;

model;
    y = (1-rho)*ybar + rho*y(-1) + sigma*e;
end;

shocks;
var e; stderr 1;
end;

histval;
y(0) = 0;
end;

extended_path(periods=500);

plot(oo_.endo_simul(1,:)); // Cannot use y variable directly here (this is a bug we need to fix).