It looks like they have a new version currently in beta. Oddly enough I have found that if I create your project completely in Eclipse 3.3.x rather than importing an a project from an older Eclipse version, it works with no problems.
A friend of mine who now works for a different company actually had some face time with the Perforce plug-in developers and (on my request) asked them about whether there was any chance of them open-sourcing the plug-in. The answer was “no” due to some proprietary code in the plug-in. Oh well it was worth a try.
New Version in Beta
It looks like they have a new version currently in beta. Oddly enough I have found that if I create your project completely in Eclipse 3.3.x rather than importing an a project from an older Eclipse version, it works with no problems.
A friend of mine who now works for a different company actually had some face time with the Perforce plug-in developers and (on my request) asked them about whether there was any chance of them open-sourcing the plug-in. The answer was “no” due to some proprietary code in the plug-in. Oh well it was worth a try.