BI Java Installation: Clarification Needed!

I'm wondering if someone could help clear this up for me:

We have installed NW2004s SPS08 on Solaris with only the usage type EP (AS Java/EP). Awhile back I was tasked with connecting our BW ABAP system to our Portal ("Integration into the Portal" - transaction SPRO etc).

After starting this task I noticed I was missing things that the instructions were telling me to configure; i.e. Items that were related to BI that weren't in the Portal such as certain roles, the BI Repository Manager etc.

Reading around, it seemed like I need to install the BI usage type.

I have now been tasked with another installation of the Portal (NW2004s SR1 this time), but am trying to head off the problems I'm experiencing trying to connect the Portal to our BW ABAP system. This will be a Java only installation. I've read that BI-Java requires EP and AS Java, and that if I install the BI-Java usage type, EP and AS-Java will be installed automatically.

My question is, if I do the BI-Java installation and it automatically installs EP/AS-Java, will the Portal still act the same way as it does in my EP/AS-Java only installation I already have? We have many plans to use the Portal as an entry point for all of our backend systems, so if the Portal's capabilities are not what we see already (in our first installation of just EP/AS-Java) then we will have problems.

Any clarification is greatly appreciated and I will award points accordingly.

THANKS!

Beau.