How to share a common customBuildCallbacks script between multiple Eclipse plug-ins

I am trying to avoid duplicating customBuildCallbacks.xml for all my plug-ins, when called from either PDE's headless build or the Eclipse GUI. I have in customBuildCallbacks.xml steps to generate code or modify the plug-in packaging that I:

• obviously want to run with the headless build

• would also like to run either when I export this plug-in from the GUI or from an external builder watching specific files in my plug-in

The headless build runs in a well defined environment, so I can set customBuildCallbacks.buildpath or even use a relative path in each plug-in's build.properties to point at my common customBuildCallbacks.xml. However, this is trickier from the GUI: that path is different for every developers since we do not have sources in the Eclipse workspace (we import projects from various locations due to our internal build process). I was hoping for every project to have an associated ant property holding 开发者_如何学JAVAits path on disk, similar to the ${workspace} variables exposed in various dialogs. I couldn't find anything useful though.

Does anyone have any experience doing this kind of things?

Thanks,

Romain