The first thing to ask are you attempting to add these for 3D conflict detection or for drawing production?
For conflict avoidance I would model the headwall as a short pipe the size of the widest part of the headwall.
If you are going to attempt this type of work around for drawing production I would use a manhole. But attempting to use a manhole as a pseudo headwall has three major issues to overcome when implemented.
1. Special manholes will need to be created in the structure file for every type of headwall for every pipe size and material type, which are to be used on the project.
2. A feature style of each headwall to match with each pipe size and with each different material type will need to be created to match with the created entries in the structure file. This will also require the user to manually change the manhole type at placement of the pseudo headwall and once placed the rotation of the manhole will need to be manually modified so the headwall aligns with the pipe direction.
3. The pseudo headwall will have to be placed "detached" from the pipe due to the hydraulics of the system will not be computed correctly with an attached manhole at the end of a pipe.
I have done this on small networks with 2-3 pipe sizes and one material type. This works great in plan when the point style has a cell for the headwall, but profiles of the network need to have the headwall added manually. One other drawback to the manhole work around is if the pipe change size or position then the manhole has to be modified separately. The good news is there are benefits to doing this work around and adding this information to the database, which are the automated reporting/quantities and labeling which can be performed on these S&S objects, whether they are a modeled as a manhole or as a pipe.
So you need to weigh when to use this workaround as to whether the benefits outweigh the extra work.
What really needs to be done is Bentley just needs to add a headwall type to the objects that can be placed by S&S.
Kevin Lucht, P.E.
Sr. Project Manager / Integrator
HNTB Corporate Ventures Division