Determine future bar indexes and dates

[neoikon]

I'm trying to determine the bar index or the date of a bar in the future.

If I go 20 bars in the future from the current bar, then I will know the bar index, but how do I determine the date of that bar? Time[] doesn't seem to work for future bars (always tomorrow's date).

Otherwise, if I know the date in the future, such as one month from today, then I will know the date, but how do I determine the bar index? GetBar() seems to always return 0 for future bars.

Is there another technique that I'm missing?

Thanks!
Daniel