Here's the snippet of the curl output. Note that 1.1.1.1 is my tomcat server and I haven't enabled the irule you suggested when doing this curl test.
curl -v http://1.1.1.1:8181/web/foo/ -H "Host:test.domain.com"
* About to connect() to 1.1.1.1 port 8181
* Trying 1.1.1.1... connected
* Connected to 1.1.1.1 (1.1.1.1) port 8181
> GET /web/foo/ HTTP/1.1
> User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
> Accept: */*
> Host:test.domain.com
>
< HTTP/1.1 200 OK
< Server: Apache-Coyote/1.1
< Set-Cookie: JSESSIONID=4E2DBF9A596207D8C8B8DD6E6664E8BC; Path=/web/; HttpOnly
< Content-Type: text/html;charset=UTF-8
< Transfer-Encoding: chunked
< Date: Tue, 17 Jan 2012 20:27:50 GMT
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 1207 0 1207 0 0 66714 0 --:--:-- --:--:-- --:--:-- 66714
100 18384 0 18384 0 0 887k 0 --:--:-- --:-
-:-- --:--:-- 8387k* Connection 0 to host 1.1.1.1 left intact