SignalR routing issue, get 200 ok but response empty - asp.net

Question

I have an existing MVC application which I am integrating a hub into, now I have setup the hub like so:
routeTable.MapHubs("myapp/chat/room", new HubConfiguration { EnableCrossDomain = true, EnableDetailedErrors = true, EnableJavaScriptProxies = true });
Then in the clientside I am connecting like so:
var connection = $.hubConnection(SystemConfiguration.ServiceUrl + "/myapp/chat/room", { useDefaultPath: false });
var hub = this.Connection.createHubProxy("ChatHub"); // Same name as on the hub attribute
connection.start().done(function(){ /* do stuff */});
Then I see the HTTP Request like so:
http://localhost:23456/myapp/chat/room/negotiate?_=1374187915970
Response Headers
Access-Control-Allow-Cred... true, true
Access-Control-Allow-Head... content-type, x-requested-with, *
Access-Control-Allow-Meth... GET, POST, PUT, DELETE, OPTIONS
Access-Control-Allow-Orig... http://localhost:34567, http://localhost:34567
Access-Control-Max-Age 10000
Cache-Control no-cache
Content-Length 420
Content-Type application/json; charset=UTF-8
Date Thu, 18 Jul 2013 22:52:18 GMT
Expires -1
Pragma no-cache
Server Microsoft-IIS/8.0
X-AspNet-Version 4.0.30319
X-Content-Type-Options nosniff
Request Headers
Accept application/json, text/javascript, */*; q=0.01
Accept-Encoding gzip, deflate
Accept-Language en-US,en;q=0.5
Content-Type application/x-www-form-urlencoded; charset=UTF-8
Host localhost:23456
Origin http://localhost:34567
Referer http://localhost:34567/myapp/chat?chatId=1764a2e3-ff6f-4a17-9c5f-d99642301dbf
User-Agent Mozilla/5.0 (Windows NT 6.2; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0
The response though contains no body, its got a 200 status though... I am debugging on the server and the hub methods are never hit. The only non standard thing in this scenario is that I have a custom CORS HttpModule which intercepts traffic and appends the CORS required headers, as you can see in the response, so not sure if this confuses SignalR's CORS support in some way. Anyway I can see the HttpModule being hit so it goes past there fine, but is somehow lost between there and the hub.
Tried googling but not much info on this topic...

Answer 1

The issue seems to be down to my CORS handling at HttpModule level, it must somehow conflict with SignalR... if I put a check in the module to see if the URL contains "chat/room" and just ignore the request if needed it then works fine, however it feels like a hack, but at least it works now.