Hmmm... have you tried submitting a Tech Link at MOTU.com? Also try asking at www.motunation.com and the Facebook page for Digital Performer.

I also have M53 but have never tried to sync it with Finale. 

I've also tried this with Kontakt as a VST instrument within Finale . . . with the same results.  Some further research indicates that Finale may not be able to transmit host tempo information to a VST instrument.  Anyone know of a workaround?  

I'm trying to think why you need to sync Tempo info to the Mach V. Are you using it to play preprogrammed sequences? If you are only using it to play sounds, I do not think you need tempo sync.

Are you trying to use Rewire or simply exporting MIDI info via the Devices panel and Score Manager, or are you porting info through Bidule or another similar module?

Kontakt and Mach V (like most AU instruments) can play both (what I'm going to call) "tempo-sensitive" and "non-tempo-sensitive" instruments. An example of a "non-tempo-sensitive" instrument might be a trumpet or violin. In that case, Kontakt just needs to know when to start and stop the notes, what the velocity is, etc. Finale does this just fine.

However, there are "tempo-sensitive" instruments which rely on the tempo of the host application (e.g. DP, ProTools, Finale, etc). A classic example of this is a loop. In the case of a loop (or other "tempo-sensitive" instrument), Kontakt needs to read the tempo from its host in order to play the loop at the desired tempo. Both Kontakt and Mach V do this just fine in other host applications (e.g. DP, ProTools, Logic).

What I'm running into is that Finale does not seem to transmit tempo information to its plugins. I've tried both Mach V and Kontakt within Finale with no luck. With these plugins, the tempo "read" from the host application (Finale) seems to be stuck at 120bpm. No tempo changes seem to be transmitted. 

In order to create new tempos, or tempo alterations within Finale I've used score expressions, the playback-controls tempo slider, and the midi tool. I've turned midi sync and MTC on and off. I've turned human playback on and off. I've tried telling HP to both incorporate and ignore tempo. I've tried everything I can think of, but to no avail.

Again, Finale recognizes and effectuates the tempo changes just fine within Finale. However, no tempo is transmitted to the plugin. The result of this is that a loop begin played by Mach V or Kontakt will only play back at the "stuck" tempo of 120bpm. So, if the tempo of my piece in Finale is 140bpm, the loop will be out of sync (Finale is playing my piece at 140bpm and Mach V is playing the loop at 120bpm).

Thank you for explaining. I do not think Finale can do what you are trying to accomplish to transfer a tempo for looping, but you can use the "Submit a request" link at the top of the screen to ask MM Support to confirm that.