Read Timed Out On TIBCO WebService Callout

Hello All,

I have a VF page which makes a web service call out on click of a button and passes on some data. The web service call out is to a TIBCO endpoint. In order to bypass firewall we have reverse proxy configured and the call out is made to the same endpoint. This worked fine until I started facing the Read Timed Out issue.
The call out still works and sends a request to the TIBCO. But I get an exception on the page displaying the error that the call out failed. In debug log, the following is displayed.

04:16:05.540 (540751323)|EXCEPTION_THROWN|[23]|System.CalloutException: IO Exception: Read timed out

The service works fine from even SOAP UI and used to work as expected in Salesforce.com as well. Right now though it is failing with the above mentioned exception.

Any idea on how to get around this?

Thanks,

Pathikrit