Not forward, Integrate so they both see the message exactly as it came from the device.
Have your devices send logs to both collectors.
That's fine for the ones that can and custom code that programmers have been smart enough to handle such. Will have to work around I guess.
Or you can wait for someone to give you a different answer. I'm sure someone else will weigh in.
It would be nice to a have special action added to the Solarwinds syslog server, that will forward in a special format that triggers Solarwinds products to bring in the message so it looks like the original from the device.
I believe that feature will be coming at some point. The Kiwi product did that and I'm assuming there are plans to bring the majority of that functionality to NPM.
As for the syslog, why do you want the syslog on both servers? Is it just to trigger the configuration download? If so, I think it might be easier if you remotely trigger it for those specific messages.
This was added as of the latest edition of NPM. The syslog server can forward messages to a second syslog server and retain the original senders ip address. Basically they copied the feature directly out of Kiwi.