Passing external regressors to rugarchspec

Hi all,

I have a pair of correlated time series of financial returns, and am using
GARCH(1,1) through rugarch to forecast realized volatilties, which I have
calculated separately. If I would like to include one series's realized
volatilities as an external regressor for the other's GARCH model, do I
need to prelag the realized volatilities before passing it to ugarchspec?

Thanks for the help,

Eric