how to postback to a different URL than the one making the request?

I'm writing an XML function that will listen for requests for data and
then respond with the data. Simple enough; however, the data needs to
be sent to the URL specified in the request. For example, the
resultant data may needed by www.123.com one time and www.abc.com
another time.

I use LWP all the time for requesting web pages, but can somebody
provide some guidance as to how LWP can be used to send data? I'm
confused.

Thanks!

RE: how to postback to a different URL than the one making the request?