Show userlabel after recon passthrough

[salmo]

I'm tying to show a custom label on the mini-map to blue players once a recon plane has gone through a pass-through trigger over the target. I'm having difficulty coming to grips with the various userlabel methods.The code below has errors. Baby steps please, explaining each method's use.

public override void OnTrigger(int missionNumber, string shortName, bool active)
    {
        base.OnTrigger(missionNumber, shortName, active);

        //RAF Dunkirk recon Do17
        if (shortName == "RAF_Dunkirk" && active)
        {   // Do17 recon'd RAF Dunkirk
            Point2d p = new Point2d();
            p.x = 221501.43;
            p.y = 252603.72;
            List<Player> BluePlayersList = new List<Player>();
            foreach (Player player in GamePlay.gpRemotePlayers()) if (player.Army() == 2) BluePlayersList.Add(player);
            Player[] BluePlayersArray = BluePlayersList.ToArray();
            double t = GamePlay.gpTimeofDay();
            GPUserLabel lbl = GamePlay.gpMakeUserLabel(p, BluePlayersArray, "RAF Dunkirk", t, GPUserIconType.Factory);
            GamePlay.gpDrawUserLabel(lbl);
        }
    }