Hello,
You can create a new feature class for any structure or line object that you need.
check the AUD help file, search using Create Feature Class, this will show you how to create a tower pole. Now you will have to use the Infrastructure Administrator program to do it, but that program can be installed as part of the AUD install. the main reason a Tower pole wasn't a part of the initial AUD feature classes is because AutoDesk pretty much just create feature classes for the RUS standard objects and a Tower isn't use much if at all in standard distribution design.
I don't use AUD any more and really haven't since AUD2009, but i hope this helps
Jim