This is a complex subject without much guidance and, what you can find will be quite technical, and difficult to put into practice. As 212man says (and as is illustrated in the procedures referenced by FlightPathOBN) there is a world of difference between an RNAV procedure and a Cat A arrival/departure.
Both of the examples provided have a proceed VFR with a distance between the 'MAPt' and the landing site respectively of 4.1 miles and 4.2 miles (in effect these are what used to be known as cloud break procedures). The Indianapolis insert does provide additional information but it is too coarse for your purposes.
Annex 14 provides a definition of surfaces that should be provided at a heliport, respectively: Approach; take-off climb; transitional; inner horizontal; and conical. If you are interested enough in these definitions, you will find them in Annex 14 Volume II. There are also several 'SketchUp' 3D (SketchUp is a free programme provided by Google) illustrations on the web. (I have used this programme to model the ICAO RNAV PINs profile in order to understand how the surfaces (and obstacle clearance) integrate with the heliport take-off and approach surfaces, in practice. I have also used SketchUp to model transitional areas for Cat A vertical procedures for from/to an elevated helipad)
For a much simpler approach (more in line with your needs) look at Figure 1-5 in AC 150/5390-2B Part 1. You should ignore the notes and, unless you need to understand US heliport guidance, concentrate only on the diagram. This just shows the provision of an obstacle surface (1:25 or 2.29 degrees) for the purpose of notification. If you decide to use this type of diagram and a Cat A vertical departure, you might need to: define your own obstacle surface; and displace the origin of the surface horizontally and vertically to correspond with your TODRH (for the helicopter) and the 'Min dip'.
Because of the difference in scales, you might also need to provide two diagrams - one showing the obstacles and departure/arrival paths surrounding the site and another, similar to the AC diagram.
This is such a complex subject that the ICAO Annex 14 working group have still to come to terms with the implication of the provision of transitional surfaces. (This might also be to do with the FAA approach that the only requirement is to provide a single (and simplistic) approach/departure obstacle clearance surface (8:1) that would be based upon a Cat B departure/arrival -not tailored for the size of helicopter.)
Hopefully, you will soon become the expert - we can then all consult you as the oracle.
Jim
Last edited by JimL; 13th Apr 2011 at 15:03.