If you attended the August Visualization SIG I showed how to create your own 3D Line Styles. The recording of this session has been posted to the LEARN Server http://learn.bentley.com/app/Public/ViewLearningPathDetails?lpId=111389 the documentation and example exercise can be found here ftp.bentley.com/visualization/3DLineStyles.zip
Enjoy!
Jerry
FTP link is no longer available/