You very well know that Web Dynpro for ABAP is available in the NW04s and you require the NW04s Portal to integrate the WD-ABAP applications into the portal and exploit all the features of the portal. But the question is, is it possible to create WD-ABAP iViews in SAP NW04 Portal (EP 6.0)? Yes, it is technically possible and this scenario is supported with certainly restrictions.
One of the most important functional restrictions is that if NW04 Portal is used to create WD-ABAP content, then the Portal Theme can not be used automatically. Instead, the stylesheet from the backend ABAP server will be used. This blog explains this restriction. While creating a WD-ABAP iView in NW04 Portal, you must specify no to using Portal stylesheet in the iView, as given below.
Once you do this, instead of using the Portal stylesheet, the stylesheet will be used from the back-end ABAP server.
The style sheet used from the app server can be viewed and maintained in the MIME repository in transaction SE80.
Another restriction from support pack perspective is that the WD-ABAP must be running on NW04s with at least SP05 or higher, and the NW04 Portal must be on at least SP13 higher. OSS Note 903662 gives a complete list of restrictions on using WD-ABAP with NW04 Portal.