It sounds to me like it is a network adapter problem on the client. If PE is seeing a loopback adapter I think the problem is not necessarily with your server. This is probably related to driver availability on the target. Make sure you have the right driver loaded in your boot WIM.
Here is a TechNet thread that describes how to do this.
There is tool at www.smartdeploy.com that uses WIM but does driver management through a console. Driver package templates are downloadable here. They might have something that can help.