Asset Management Application: E-R Model

In one project for a class (ISYS 464 Enterprise Data Management), I created a small asset management application that could be used for information technology support group to track the assets such as software, hardware, and support contracts.  These would store the order information and reseller information, in case this needed to be referenced (such as a return or getting service).

Here's a simple Entity-Relationship model.

The crazy part of this is that the asset can be three different types of assets: support contracts, software, and hardware.  The support contract can support a software asset or a hardware asset.

The asset itself can be assigned to a user, managed by support, and purchased (owned) by a manager, all of which are some type of employee.  There's not distinction in the type of employee, other than has the asset relates to the employee (owner, user, supporter).

So the question is how can this be easily represented?