10g AS - what do I need?

I've Googled every possible combination of keywords, & read white papers & PDFs until my eyeballs have fallen out, but I'm getting nowhere fast. I hope one of you guys will take pity on me here...

Basically I need to do something very similar to http://www.oracle.com/technology/sample_code/tech/java/jsp/samples/wscli ent/Readme.html but with a couple of important differences:

1. I need to do it in 10g.
2. My equivalent of the 'Credit Agency Web Service' is on a secure server, so I need to register their keys (PFX & P7B apparently).

My first problem is I can't work out what I need to download & install, apart from the 10g database. The AS download page lists two flavours -
'Portal & Wireless', and 'J2EE & Webcache'.

I've downloaded the former as it includes 'AS Certificate Authority' which sounds like it might be required. When I start the installation, it give three options: 'Application Server', 'AS Infrastructure' and
'AS Developer Kits'. The first option includes HTTP Server & OC4J, both
of which I think I need. The second option includes the Certificate Authority, which I'm guessing I also need. Does that mean I have to install both options? If so, I tried that, & it wouldn't let me install both in the same home - which makes me think I'm being stupid & missing something obvious.

I'm sure I'll hit plenty of other obstacles along the way, but for now I'd just be happy knowing what I need to install. Any help VERY gratefully received!

Oh, it's Win2k server btw.

-- 
Preston.