A Portal to a Portal

I searched for "Rational Application Developer" and found: -

IBM Rational Application Developer for WebSphere V7.5 Multilingual Multiplatform eAssembly (Optional) (CR7NQML)

which includes, amongst other things: -

W-Setup IBM WebSphere Portal Server V6.1.0.1 - IBM WebSphere Portal Server Install V6.1.0.1 (W-Setup, A-Setup, H-Setup, HI-Setup, I-Setup, IL-Setup, PL-Setup, ZL-Setup, SS-Setup, SO-Setup) Multiplatform Multilingual (C1TL1ML)

W-1 IBMWebSphere Portal V6.1.0.1, WebSphere Portal Express V6.1.0.1 and Lotus Web Content Management V6.1.0.1 - IBM WebSphere Application Server Network Deployment for Windows x86-32, V6.1.0.19 (W-1) Multilingual (C1TQ5ML)

W-2 IBM WebSphere Portal V6.1.0.1 and Lotus Web Content Management V6.1.0.1 - IBM WebSphere Application Server Network Deployment for Windows x86-64 (W-2) Multilingual (C1TR1ML)

W-3 IBM WebSphere Portal Server V6.1.0.1 - IBM WebSphere Portal Server Server component (Disk 1 of 4) V6.1.0.1 (W-3, A-3, H-3, HI-3, I-3, IL-3, PL-3, ZL-3, SS-3, SO-3) Multiplatform Multilingual (C1U2UML)

W-4 IBM WebSphere Portal Server V6.1.0.1 - IBM WebSphere Portal Server Server component (Disk 2 of 4) V6.1.0.1 (W-4, A-4, H-4, HI-4, I-4, IL-4, PL-4, ZL-4, SS-4, S0-4) Multiplatform Multilingual (C1U2XML)

W-5 IBM WebSphere Portal Server V6.1.0.1 - IBM WebSphere Portal Server Server component (Disk 3 of 4) V6.1.0.1 (W-5, A-5, H-5, HI-5, I-5, IL-5, PL-5, ZL-5, SS-5, SO-5) Multiplatform Multilingual (C1U30ML)

W-5a IBM WebSphere Portal Server V6.1.0.1 - IBM WebSphere Portal Server Server component (Disc 4 of 4) V6.1.0.1 (W-5A, A-5A, H-5A, HI-5A, I-5A, IL-5A, PL-5A, ZL-5A, SS-5A, SO-5A) Multiplatform Multilingual (C1U34ML)

This document: -

Required CDs and downloadable images to install IBM WebSphere Portal Server v6.1.0.1

describes the download and extraction process in more detail.

This document: -

Parts required for WebSphere Portal Test Environment 6.1 install in Rational Application Developer 7.5.x

looks to be even more relevant to your requirements.