Eclipse 3.3 - org.eclipse.ui.IContributorResourceAdapter cannot beresolved

[Rob.Best]

My apologies in advance if this is the incorrect group to post this
question to. If it is please point me in the right direction.

I'm developing an Eclipse 3.3 targeted RCP and am using the P4WSAD
plugin. A class (DepotViewFile) from P4WSAD implements the
org.eclipse.ui.IContributorResourceAdapter interface and when I try to
use this class in my code I get an unresolved error. When I try to
import org.eclipse.ui.IContributorResourceAdapter I get a similar
error about the import not being resolved.

Looking through org.eclipse.ui.workbench_3.3.1.M20070921-1200.jar I
see that indeed the org.eclipse.ui package contains no
IContributorResourceAdapter interface despite it being listed in the
3.3 docs.

I have updated everything in Eclipse, and still have no success. Does
anyone have any ideas on this?