1) Install using 8.5.0-Alpha update site into clean JBDS:

Cannot complete the install because one or more required items could not be found.
  Software being installed: Teiid Designer Runtime 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.designer.runtime.feature.feature.group 8.5.0.Alpha1-v20140421-1409-B2575)
  Missing requirement: Core Designer Plug-in 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.core.designer 8.5.0.Alpha1-v20140421-1409-B2575) requires 'bundle org.jboss.tools.locus.sf.saxon [9.2.1,10.0.0)' but it could not be found
  Cannot satisfy dependency:
    From: Relational Plug-in 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.designer.relational 8.5.0.Alpha1-v20140421-1409-B2575)
    To: bundle org.teiid.core.designer [8.1.0,9.0.0)
  Cannot satisfy dependency:
    From: Teiid Designer Runtime 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.designer.runtime.feature.feature.group 8.5.0.Alpha1-v20140421-1409-B2575)
    To: org.teiid.designer.relational [8.1.0,9.0.0)

2) Install using 8.5.0-Alpha update site - overlay after intalling Designer 8.3.2 first:

Your original request has been modified.
  "Teiid Runtime Clients" is already installed, so an update will be performed instead.
  "Teiid Designer Runtime" is already installed, so an update will be performed instead.
  "Teiid Designer" is already installed, so an update will be performed instead.
  "Teiid DataTools Connectivity" is already installed, so an update will be performed instead.
Cannot complete the install because one or more required items could not be found.
  Software being installed: Teiid Designer 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.designer.feature.feature.group 8.5.0.Alpha1-v20140421-1409-B2575)
  Missing requirement: Teiid DataTools Connectivity 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.datatools.connectivity.feature.feature.group 8.5.0.Alpha1-v20140421-1409-B2575) requires 'org.eclipse.birt.report.data.oda.hive.ui [4.3.2,5.0.0)' but it could not be found
  Cannot satisfy dependency:
    From: Teiid Designer 8.5.0.Alpha1-v20140421-1409-B2575 (org.teiid.designer.feature.feature.group 8.5.0.Alpha1-v20140421-1409-B2575)
    To: org.teiid.datatools.connectivity.feature.feature.group [8.5.0.Alpha1-v20140421-1409-B2575]