Well, since it's a scheme library function I should think that you'd be accessing it with '$ or 'mz, both of which (if I remember correctly) send all of the symbols in their arglist directly to scheme without any arc transformations first.
So ($.exn:srclocs args) should work, or maybe just
(($ exn:srclocs) args) presuming of course that you've loaded the requisite lib files.
