Dawa,
It could be a lot of different things, it all depends on the exact encoding scheme they've used. Look at the XMLAdapter.DisableEncode for one set of options. If that doesn't work you may be able to use strconv() to decode the data.
>A client is sending me a Hex Binary Object within an XML element. I'm supposed to extract it and convert it into a binary file.
>
>What is a Hex Binary Object? How do I convert it?