Hi Mark,

OK, here goes with a few answers:
1) I have not seen any devices use user defined headers to send generic information, this doesn't mean there are not any devices out there that do it to communicate in a non-standard way, just that I have never seen them.
2) Generally speaking most devices that you can program to send specific things can have the name field set pretty easily, and using the extention is a good way to do things (that is how a lot of the existing OBEX implementations work) and most devices that allow you to beam objects use the name.format option.

There are some new standards which I don't think are in the public domain yet, that do not use the name field at all, instead they use a targeted connection to let the server know how to route the data by adding the target header (0x46) and a known UUID, check out the section 'known target identifiers' in the spec if you need more information.

The correct way to route information would be to work through the headers in order (of importance, not the order in the packet) and once you find one with some information, use that to route the information you have.

If you have specific questions about IrDA or OBEX feel free to ask, and I can probably answer, although maybe not in a public forum, and as for just telling you what I know, when I handed off that work to its new maintainer it was a 2 month process, so it is not as easy as just tell me everything.