vertical line on chart

[nl100]

I use amibroker 6.00. I have 20 min, 2 hrs and 12 hrs charts. I wish to draw a vertical line at a specific point on the chart and the point corresponds to the trading hours ( 9.30AM) start on a date equal to 5 days before current day on all charts mentioned above. I have not been successful in achieving this. Would it be possible for someone to help me with this ?