@RequestMapping, URITemplate and optional path parameters

I have the following mapping:

Code:

---

@RequestMapping(value = "/{first}/**/{last}", method = RequestMethod.GET)
public String test(@PathVariable("first") String first,  @PathVariable("last")  String last) {}

---

Which for the following URIs:
foo/a/b/c/d/e/f/g/h/bar
foo/a/bar
foo/bar

maps foo to first and bar to last and works fine.

What I would like is something that maps everything between foo and bar into a single path param, or null if there is no middle (as in the last URI example):

Code:

---

@RequestMapping(value = "/{first}/{middle:[some regex here?]}/{last}", method = RequestMethod.GET)
public String test(@PathVariable("first") String first,  @PathVariable("middle") String middle, @PathVariable("last")  String last) {}

---

Pretty stuck on the regex since I was hoping that something simple like {middle:.*}, which only maps to /foo/a/bar, or {middle: (.*/)*}, which seems to map to nothing.

Does the AntPathStringMatcher tokenize upon "/" prior to applying regex patterns? (making patterns that cross a / impossible) or is there a solution?

FYI on Spring 3.1M2