Tempete: I could be mistaken about this, but I think that in Vector Linux, Xarchiver is included as part of the general Xfce package. So, if you install VL, Xarchiver is automatically included with Xfce. From the Xfce web site it seems that Xarchiver can be built separately, but it seems to have been built as part of Xfce with VL. That's probably why it isn't in the repositories.
Perhaps I misunderstood your question. Are you missing Xarchiver?