Connection to external xml file

How do I use an external xml file as a data source for my LiveCycle form?

I have an xml file on my server that is updated every few days by a script. My LiveCycle form is on the server and can be pushed to the client by the click of a button on a web page or similar. Is it possible to have the LiveCycle form refresh its data before being sent to the client, or every few days?

I was thinking that on the load of the form, a JavaScript function could check if the form is on the server, or check if the xml file is there, and if it is, update itself, else do nothing.

I would rather keep the xml file and the form seperate as other applications and scripts make use of the xml file.

Thanks.