xml file format, help

[nexusm]

Hi, all.
I have created for a client for a part of his business a software which automatically generates an invoice / invoices to his clients (nothing out of usual).
The accountant of my client is using a software in order to keep the books which allows him to import the invoices in xml format. My software doesn't issue the invoices in xml format, so I have to solve the problem.
He has given me a copy of such xml invoice asking me to try to create the invoice in the same format.
I have succeeded to create the xml file containg the necessary data and information and in the necessary order.
When I made the import test the accountancy soft gave an error message.
I suppose that the file properties has some particularities like ISO, UTF-x, etc.

Question: IF I have an original invoice how can I read those properties in order to create and encode my xml file to be exactly the same?
Few line of code or some links will be appreciated and/or comments required

Thanking you in advance for any help or suggestions.

[GeoffB17]

Hmm, would have been nice if you'd said what the error message was.

As I understand it, xml is pretty flexible. Basically using html <tag>data</tag> instead of fixed char counts (sdf) or cr/lf or literal separators to present data.

His receiving process is expecting a certain sequence of data, you need to provide that. It would seem your process was NOT?

I would have thought the error message may give a hint. Did the error message include a line number?

I assume that you were given an xml file that would create the invoice. That file should provide all the info to mimic.

Geoff