I just found a BIG bug with <antcall> task.
 
If you use <path id="..." > at least at the project level, <antcall> will fail complaining during the second parsing of the file.
 
I guess this is because ids are not replaceable in subprojects. This looks wrong to me.
The subproject ids should override the one in the calling project for the duration of the call.
 
Jose Alberto