There's no official formatting of ISWC codes.
MB chooses T-XXX.XXX.XXX-X but e.g. T-XXX.XXX.XXX.X is valid too.
So URL such as http://musicbrainz.org/iswc/T-702.152.911.5 should work (currently only http://musicbrainz.org/iswc/T-702.152.911-5 works)
There are also T- 702.152.911-5 (as in JASRAC) and T7021529115 (as in SACEM) not found.
It could actually rewrite URL to understand any by