Just to be clear, I am still not sold on the idea of touching EIS name as the API is "in the wild". That said, and terminology aside, what we need is some way to know at which entity an XID was generated so that the recovery manager can detect it is an orphan. I have been calling these node names, as the exisiting terminology is "nodeIdentifier". Remember though, these are transaction manager "nodes", not nodes as in hosts. Potentially there can be more than one transaction manager node per host and each of these will need to be given a unique persistent identifier. This is an existing and established requirement of JBoss TS.
I am not sure if I am misintrepetting Mark or David here but I think Mark was suggesting putting the EIS name to EIS XID key into a configuration file so that we can then fit in the node name as a String as David would like. I was saying that is not great as either the established API needs to change to pass us the key or we take a performance hit of resolving the key in the configuraiton file. Plus at the moment we are preferably going to put two node identifiers in the bqual.
In either scenario, the administrator is going to need to keep a mapping file. Either remoting node identifier to transaction manager node name (my preference) or EIS name to EIS int key.