I haven't had to work with xml but...
When you select Export Records from the file menu, you'll see xml listed as one of the file types to which you can export your data. That may get you started in the right direction.
XML is a very loose specification. You need to find out the exact grammar (schema) that the target application requires.
Filemaker exports xml in two grammars, FMPXMLRESULT and FMPDSORESULT. In addition, you can use a custom XSLT stylesheet to transform the export into practically any grammar.
You're right. I'll try to find out more information and hopefully I'll be able to figure this out.
Thank you for your help.