oofs = (OpenOfficeDocFileSystem)getMountedDocument(rootFile);
if(oofs != null)
repo.removeFileSystem(oofs);
oofs = new OpenOfficeDocFileSystem();
oofs.setDocument(rootFile);
repo.addFileSystem(oofs);
return oofs;
}
/** @return FileSystem which has given jar file as its root or
* null if no such file system could be found in repository */