Complicated Chart

I'm trying to create a complicated graph in code and display it. The graph has 2 series of points, two least square curves, and vertical/horozontal lines.

I've gotten excel to plot the points (XY scatter) and the curve (trendline, polynomial, 2 degree), but I cant get it to draw my lines (2 horz., 2 vert.)

I've gotten my code (.NET/interop) to add the right trendline, but cant get it to plot the points right, or draw the lines I need.

any help in either space would be greatly appreciated!

-----
VS(VB) 2003

referance:
Microsoft Graph 10.0 Object Library

try to record a macro, then grab the code from there