Currently the only ways to get drools/jbpm 5 plugins installed into Eclipse are to:

a) download the org.drools.updatesite-*-assembly.zip zip from Nexus, or
b) unpack the droolsjbpm-tools-distribution-*.zip linked from http://www.jboss.org/drools/downloads, or
c) use the nightly staging site for JBT SOA Tooling http://download.jboss.org/jbosstools/updates/nightly/soa-tooling/trunk/
d) use the nightly staging site for JBDS SOA Tooling http://www.qa.jboss.com/binaries/RHDS/builds/staging/devstudio-5.0_trunk.soa-tooling.updatesite/product-soa/

Since the JBT site (c) is going away, and (a) and (b) are a relative pain in the butt, we need a new unpacked site, eg., under here:

http://download.jboss.org/drools/updates/
or
http://download.jboss.org/drools/releases/

For JBoss Tools, the convention we use is:

http://download.jboss.org/jbosstools/updates/stable/ (releases)
http://download.jboss.org/jbosstools/updates/development/ (milestones and candidate releases)
http://download.jboss.org/jbosstools/updates/nightly/ (bleeding edge CI builds)
http://download.jboss.org/jbosstools/updates/ (see this page for further discussion of the build types)