I'm glad you're interested. However, I'm not sure if manual rotations are what I'm after.
The thing I'm talking about is a way to make CAD automaticaly align and rotate entites based on a rules you define.
This is really powefull tool, however, this link I provided (and refered to as gold) is the only other (beside Jeffs) available online!
There is also another link to blog of how to apply blocks to each polyline vertice, but I'm unable to find it. I literally opened hundreds of pages this weekend, trying to find something, so It's kind of lost in browser history.
Also, not directly related, but interesting:
http://adndevblog.typepad.com/autocad/2012/03/working-with-associative-parameters-from-api.htmlThe link I provided is a complete enough, however, I have no idea of what goes where. For example, line has edges - what text has? How to find point of interest for text?...
I think Jeff H could help maybe...